THE

CAMBRIDGE NATURAL HISTORY

EDITED BY

S. F. HARMER, Sc.D., F.R.S., Fellow of King's College, Cambridge; Superintendent of the University Museum of Zoology

AND

A. E. SHIPLEY, M.A., Fellow of Christ's College, Cambridge; University Lecturer on the Morphology of Invertebrates

VOLUME IX

BIRDS

London
MACMILLAN AND CO., Limited
NEW YORK: THE MACMILLAN COMPANY
1899

All rights reserved

In this volume of the "Cambridge Natural History" the author has attempted to meet a need which he believes to be somewhat widely felt. Recognising the fact that there is at the present time an abundance of popular, or only slightly scientific, works on Birds, some of which touch but superficially upon the individual species composing the various groups, as regards their plumage or habits, while others pay little or no attention to correctness of Classification, he has essayed the difficult and apparently unattempted task of including in some six hundred pages a short description of the majority of the forms in many of the Families, and of the most typical or important of the innumerable species included in the large Passerine Order. Prefixed to each group is a brief summary of the Structure and Habits; a few further particulars of the same nature being subsequently added where necessary, with a statement of the main Fossil forms as yet recorded.

Thus it is hoped that the work may be of real use, not only to the tyro in Ornithology, but also to the traveller or resident in foreign parts interested in the subject, who, without time or opportunity for referring to the works of specialists, may yet need the aid of a concise account of the species likely to cross his path.

An introductory chapter has been written, to meet the claims of the present day, on the external and to a limited extent on the internal structure of Birds, with short paragraphs on {vi}Classification, Geographical Distribution, and Migration, and a "Terminology" of the subject.

In accordance with the scheme of the Series generally, the order followed runs from the lowest forms and the Ratite Birds upwards; the Carinate Birds being divided, after Dr. Gadow's plan, into two Brigades or main sections, and these again into Legions, Orders, and so forth. It should, however, be understood that the Species of each Genus are often merely placed in the most convenient order; and that, where a geographical range is given, it does not follow that it is unbroken from end to end.

In descriptions of colour, the names used for tints in the British Museum Catalogue of Birds have been commonly adopted, or for British species those in Mr. Howard Saunders' Manual of British Birds.

Various subjects of a highly technical, or at least of a special character, have purposely been avoided in the main, as unfitted to the scope of the work; such are, Variation and Hybrids, with their accompaniments of Dimorphism, Dichromatism, and the like; Myology; Mechanism of Flight and the supposed Lines of Flight on Migration; the Classifications of Linnæus and the older writers; and the Strickland Code of Ornithological Nomenclature. For these Professor Newton's Dictionary of Birds, and especially the Introduction to it, may be consulted; besides a multitude of other works.

The woodcuts have been chiefly supplied by Mr. G. E. Lodge; but a few illustrations have been utilized from other sources.

The author does not hold himself responsible for the fact of the Family names being in Roman in place of Italic type, nor for the dissociation of the vowels in the diphthongs; in these minor points he personally differs from the writers of the former volumes, though he agrees with the wish of his Editors for uniformity.

In conclusion, he must take the opportunity of acknowledging the invaluable assistance afforded by Mr. Howard Saunders, who carefully went over the whole of the proofs, while Dr. R. B. Sharpe was kind enough to do the same; nor must he fail to record his indebtedness to Professor Newton, Mr. Sclater, Dr. Gadow, Mr. Ogilvie Grant, and many others, not to mention the innumerable authors without whose previous labours to write a book of this description would be a well-nigh impossible task. Dr. Stejneger's Volume on Birds in the Standard Natural History should be mentioned in particular.

Since the text has been printed off, several new species have been described, and of these it is necessary to mention at least the following;–

Archaeopteryx siemensi, from Solenhofen, where the original form was obtained.–(Dames.)

Euryapteryx exilis (Dinornithidae); a new genus, Anomalornis, is also proposed for Anomalopteryx (preoccupied).–(Hutton.)

Ammoperdix cholmleyi (Phasianidae), from Suakin.–(Ogilvie-Grant.)

Cepphus snowi (Alcidae), from the Kurile Is.–(Stejneger.) The range of C. columba will now be "Bering Sea to California;" and of C. carbo "North-East Asia and Japanese Seas."

Podoces pleskii (Corvidae), from East Persia.–(Zarudny.)

Some new fossil forms from Patagonia.–(Mercerat.)

Mr. F. E. Blaauw has published a Monograph of the Cranes, and Mr. C. W. de Vis has described the eggs and young of Salvadorina (Anatidae).

In all these cases the Zoological Record for 1897 may be consulted.

INTRODUCTION

Definition.–"A Bird is a feathered biped." This popular saying undoubtedly furnishes a definition in the world of to-day, since no other existing creature has a clothing of feathers, and even the word "biped" is thus superfluous.

The above should, however, be somewhat expanded, in order to shew in greater detail the differences between Birds and other Vertebrata. Care must nevertheless be taken to avoid the fault common to many modern definitions, of giving an abstract of the main characteristics of the object, rather than a clear guide to distinction.

Dr. Gadow^[1] defines Birds as "oviparous, warm-blooded, amniotic Vertebrates, which have their anterior extremities transformed into wings. Metacarpus and fingers carrying feathers or quills. With an intertarsal joint. Not more than four toes, of which the first is the hallux."

Much of this the beginner might well postpone, his attention being solely drawn to the external characters; though of course those that are internal are by no means to be subsequently neglected. Indeed no satisfactory progress can be made in the serious study of Ornithology, or the Science of Birds, without a competent knowledge of their Anatomy and Development; while, though at present comparatively few fossil remains of Birds have been found, some of them are of the highest importance, and there is every probability of future discoveries throwing much light not only on the mutual relationships of Birds among themselves, but also on their connexion with the Reptilia. Birds are, in fact, only extremely modified Reptiles, the two Classes forming the Sauropsida of Huxley, one of his three primary divisions of Vertebrata. {2}The aid of the Palaeontologist and Geologist must thus be called in to clear up many problems which present themselves to the Ornithologist who does not content himself with examining existing forms of life alone. Archaeopteryx (p. 23) from the Jurassic System is the oldest Bird known, nor are any other pre-Tertiary forms recorded, save a small number from the rocks of the Cretaceous Epoch, the chief of which are the so-called Odontornithes, or toothed species of America (p. 45).

The following paragraphs on the structure of Birds will help to explain the systematic account in the later chapters.

Feathers.–Returning to the outward character denoted by the popular saying with which we began, the Feathers^[2] constituting the plumage may not inconveniently be first considered. The general belief that they grow from almost every part of a Bird's body, as do hairs in most Mammals, is erroneous; for, almost without exception, they grow in certain definite tracts called pterylae, the intervening spaces, whether they be wholly bare or covered with down, being termed apteria. The arrangement of these patches is at times of considerable assistance in determining a Bird's affinities; and the subject may be studied in Nitzsch's Pterylographie^[3] or in a shorter form in Dr. Gadow's article "Pterylosis" in Professor Newton's Dictionary of Birds.

A feather originates thus. A conical papilla arises in the derma and pushes up the epidermis, a depression forming meanwhile around the base; subsequently the derma supplies a nutritive pulp, while part of the epidermal layer is converted into a tuft of stiff rays, meeting and forming a short tube below; these thereafter burst their covering and protrude as the rami or barbs, on which, apparently by secondary splitting, are commonly produced radii or barbules. In this state we have a plumule or "down-feather"; but in the case of the feathers that have "webs" or "vanes" (vexilla) often called contour feathers (pennae or plumae), a fresh papilla forms at a deeper level, so that the earlier structure is thrust forward and eventually drops off from the apex of the later. Meanwhile the "dorsal" portions of {3}the barrel or quill (calamus or scapus) at the base of the tuft of rays have elongated into a principal shaft (rhachis); this is generally accompanied by a secondary "aftershaft" (hyporhachis), originating from the "ventral" side, which in the Emeu and Cassowary rivals the shaft itself in size. On the rhachis a double series of lamellae or barbs are developed, carrying a similar double series of barbules, much as in the down-feather, but the barbules again give rise to barbicels (cilia), which in the distal rows usually terminate in hooklets (hamuli). These catch in the folded margins of the next proximal row, and a firm surface is thus secured. An after-shaft never, and a down-feather rarely, possesses barbicels; while in some cases by the absence of these and part of the barbules a "disconnected" web and a "decomposed" feather are formed, as in the decorative tufts of many species. The barbs may even be absent, as in the wing-quills of Cassowaries, the wires of Birds-of-Paradise, the "bristle-feathers" at the gape of Night-jars or the eyelashes of Hornbills. In the hackles of Gallus (Fowl), and the secondaries or even the tail-feathers of Ampelis (Waxwing), the tip of the rhachis is flattened and wax-like; and similar structures are observable elsewhere. In the newly-hatched young the down is often partly or entirely suppressed, but in certain Birds this suppression is temporary, and a thick coat grows after a few days. "Powder-down" feathers are those which never develop beyond the early stage, and continually disintegrate at the tip into bluish- or greyish-white powder; they occur in the Tinamidae, Ardeidae, Rhinochetidae, Eurypygidae, Mesitidae, Accipitres and Psittaci, in Podargus, Coracias, Leptosoma, Gymnoderus and Artamus.

Colour.–The colour of Feathers is due to one of three causes. First, an actual pigment^[4] may be present in certain corpuscles, or in diffused solution, and the tint does not then vary according to the incidence of the light. Secondly, it may arise from a pigment overlaid by colourless structures in the form of ridges or imbedded polygonal bodies; here, if the vanes are scraped or held up to the light, the pigmentary colour alone is visible.^[5] Thirdly, the colour may be iridescent or prismatic; that is, a blackish {4}pigment may lie beneath a surface, which, whether polished, ridged, or pitted, acts as a series of prisms, causing the hue to vary according to the relative position of the spectator's eye and the light. This is seen in a remarkable degree in Humming-birds.^[6]

Not uncommonly the vanes of feathers have an appearance like watered silk, due to very indistinct transverse striations. In regard to plumage generally, it may be noticed that the markings on a feather frequently indicate the age of a bird. In some the immature plumage is characterised by light-coloured tips to the feathers, which are lost as maturity is reached. In other groups, and especially in most of the Accipitres or Diurnal Birds of Prey, the markings of the immature bird are generally longitudinal, and in the adult transverse. In nearly all these cases the change is effected at the first moult. Females and young are usually duller than males, but in some cases, such as Phalaropus (Limicolae) and Eclectus (Psittaci), the hen-birds are the more brightly coloured.

Moult.–Referring to p. 2, it should be remarked that, after the production of a feather, the formative substances become for a while dormant, but awake to renewed activity, if accidental or periodical loss needs to be made good; and so we naturally arrive at the phenomena of the annual Moult, which is often double, that is, occurring towards autumn, and again in spring.

Though some Birds do not lose their quill-feathers the first year, they normally gain a winter plumage–differing in colour from the summer garb–by moulting or shedding their feathers. The wing-quills, and even those of the tail, are ordinarily discarded in pairs, though not quite simultaneously; but most Anatidae (Swans, Geese and Ducks), and apparently the Phoenicopteridae (Flamingos), lose all the former at once,^[7] and with them the power of flight; while in the first-named Family the males of many species assume for several weeks a dress resembling that of the female, and are said to undergo an "eclipse." Young birds moult, as a rule, somewhat later than adults, but in the typical Gallinae the original quills are shed before the possessors are fully grown, and are succeeded by others of proportionately increased size, the power of flight being attained very early.

The additional or spring moult affects the smaller feathers only, while it is still doubtful how far changes of colour are clue to a mere dropping off of the fringe of barbicels. The decorative plumes of the males of many species are gained at the vernal moult. The double process is certainly not diagnostic of Families or even Genera, except in isolated cases; as an instance, however, the Larks have one moult, the Pipits and Wagtails two.

In such cases as Swallows and Diurnal Birds of Prey generally, the plumage is not changed till after the migration; in the Ptarmigan there is a triple moult, the breeding-suit being changed first to a greyish habit and then to a white; in Penguins the feathers of the wing come off in flakes.^[8]

Skeleton, Digestive Organs, etc.–The plumage, however, though often striking, and of undoubted utility as a non-conductor of heat and a protection against wet, plays a subordinate part in determining the relationships of the larger groups of Birds. For this we need the assistance of anatomy, if indeed we do not rely upon it almost entirely. It will be well before starting to state that structures which are morphologically similar, that is, which have a like origin in the embryo, are termed "homologous," while those which perform the same physiological functions are "analogous," the word in its strictest sense implying initial diversity.

Any standard work on Vertebrate Anatomy ought to furnish a concise account of the bony framework or Skeleton of a Bird, but it will be convenient here to follow mainly the treatment of Dr. Gadow, in Prof. Newton's Dictionary of Birds, pp. 848-867.

According to this authority the Axial Skeleton consists of the Skull and Vertebral Column; the Appendicular Skeleton of the Ribs, the Sternum, the Limbs and their Arches, the Hyoid Apparatus or framework of the tongue, and the Jaws.

1. The Vertebral Column, which protects the Spinal Cord, is composed of a variable number of cervical, dorsal, sacral or pelvic, and caudal vertebrae; that is, those of the neck, back, loins and tail respectively. The first cervical vertebra, which bears the head, articulating with it by a single condyle, is called the Atlas; the second, on which it turns, the Axis; the succeeding cervicals {6}present a considerable number of processes or projections, which protect certain blood-vessels, and serve for the attachment of the muscles which turn the flexible neck. The dorsal vertebrae follow, and some not unfrequently coalesce with each other, but this is always so with the sacrals, and in nearly all existing Birds with the terminal portion of the caudals, which are fused together to form a "pygostyle" or upright triangular plate to carry the tail-feathers.^[9] Archaeopteryx, so far as is known, stands alone in having all the caudal vertebrae free.

A typical vertebra consists of a centrum, and an arch, with articular surfaces for two ribs, and is called heterocoelous when the facets, or connecting surfaces, are saddle-shaped, a condition characteristic of, and restricted to, Birds. It is amphicoelous, or biconcave, when each end is hollowed, as in the dorsal region of Ichthyornis and probably in Archaeopteryx; procoelous, when concave in front (as is common in Reptiles); opisthocoelous when concave behind (as in many Mammals).

2. The Ribs are doubly attached to the vertebrae by a head (capitulum) and a knob (tuberculum); and have a neck, a dorsal, and a ventral portion, each dorsal section (save on the last rib) possessing an "uncinate process" or thin, bony posterior projection, except in Archaeopteryx and the Palamedeidae. Should the ventral piece articulate with the sternum the rib is "true," otherwise it is called "false"; moreover the cervical and frequently the post-thoracic ribs are fused with the cervical vertebrae and the ilia respectively.

3. The Breast-bone (Sternum) presents two different styles–according to whether it exhibits on its ventral surface a median ridge or keel (carina), or not. In the former case, which is that of by far the greater number of existing Birds (hence termed Carinatae), the keel is of variable size, being correlated with the power of flight. It is exceedingly deep in the Swifts, Humming Birds, and certain Petrels, but dwindles almost to disappearance in some flightless forms such as the Dodo, the Kakapo (Stringops), the extinct New Zealand Goose (Cnemiornis), and a good many Rails.

The absence of a keel is characteristic of the other and smaller group of Birds, made up of the Ostrich, Rhea, Emeu and Cassowary, Moa and Kiwi, which from the resemblance the sternum thus bears to a flat-bottomed boat (ratis) are known as Ratitae. Whether keeled or not, the breast-bone affords a surface of attachment to the principal muscles of the fore-limbs, and its anterior end supports the coracoids, as in Fig. 2. Various processes are in most cases developed on the sides of the sternum itself, behind its junction with the ribs, especially towards the {8}posterior portion, where they often take the form of prolongations, the extremities of which occasionally meet and enclose what are called fenestrae; but these are unimportant when compared with the features presented by the anterior part.

4. The Pectoral Arch, or Shoulder-Girdle, consists of three pairs of bones, the Coracoids, the Scapulae or Shoulder-blades, and the Clavicles or Collar-bones, the last two usually coalescing in the median line into a V-shaped or U-shaped Furcula (the well-known Merry-thought); but in some groups, as certain Parrots, the clavicles are practically absent, while in others, as several Owls, they do not unite. The furcula often ossifies firmly with the anterior portion of the keel, and in Fregata, Didus and the Ratitae, the coracoids and scapulae are fused together.

5. The Anterior Limbs, or Wings, are composed of the Humerus, or upper arm-bone, the Ulna and Radius (making the fore-arm), the Carpus or wrist, the Metacarpus and Digits, corresponding with the hand and fingers. The first of the three metacarpals bears the Pollex, or thumb, with one or two {9}phalanges (joints); the second the Index, representing man's first finger, with two or three joints; the third a weak digit with only one phalanx, except in Archaeopteryx, where there are four. The Casuarii and Apteryges possess an index only, which in the Sphenisci fuses with the pollex. The basal joint of this is the normal place of attachment of the "bastard wing" (alula spuria). Archaeopteryx had claws on all its fingers, but in recent Birds they occur on the first two only, being functionless in the adult. Wing-spurs arise from the carpal and metacarpal bones.

6. The Pelvic Arch consists of the Ilium, Ischium, and Os pubis, these three paired bones meeting from each side at the cup (acetabulum) that receives the head of the femur, and coalescing early in life; while the incisura ischiadica or notch between the ischium and the ilium becomes an inclosed space (foramen) in all Birds except the Ratitae and Crypturi.

7. The Posterior Limbs, or Legs, are composed of the Femur or thigh, the Tibia and Fibula, making the shank or "drumstick," and the bones of the Foot. The thigh, however, being hidden by the plumage, the shank of a Bird might easily be taken for the thigh, and the metatarsus (the cannon-bone of some) for the shank. The tibia and fibula commonly unite to some extent, and the former, as it now exists in adult Birds, is strictly a "tibio-tarsus," since with it is fused the proximal portion of the originally existing tarsal elements. Similarly the distal tarsal {10}elements unite with the metatarsus, which is therefore properly a "tarso-metatarsus," though often called merely "tarsus" by ornithologists. This arises from a fusion of the second, third, and fourth metatarsal bones, which in the adult (except among the Sphenisci and to some extent in Psittaci) do not lie in the same plane; the middle one having its upper end thrust backward and its lower end forward in the course of growth to maturity. The fifth metatarsal practically disappears, while the first remains more or less separate, and lies behind the distal portion of the other metatarsals.

Of the toes the fifth is not traceable in Birds; the first is often aborted, but the second only in Struthio, and to a less extent in Ceyx and Alcyone, and the fourth (nearly) in Cholornis. The hallux, or hind toe, has two phalanges, the second digit three, the third four, and the fourth five; Cypselus and Panyptila (Swifts), however, are exceptions, and possess only three in each of the anterior toes, while the Caprimulginae (true Nightjars) and Pteroclidae (Sand-Grouse) have only four joints on the outer. In Owls the fourth digit is reversible at will, the same being true to a less extent of the Musophagidae (Plantain-eaters) and Leptosoma (akin to the Roller); when this condition is permanent, as in the Cuculidae, Psittaci and Pici the foot is termed zygodactylous. In Trogones the second toe is reversed (heterodactylous). Colius can turn the first toe forward and the fourth backward, while certain Swifts, and to a less degree some Nightjars, have the whole number permanently pointing to the front (pamprodactylous). Membranes more or less connecting the anterior digits produce a webbed or swimming foot, even the hallux being united with the rest in the Steganopodes. The hind-toe is often elevated, or higher than its fellows, when it is commonly reduced and sometimes lacks a nail. The Ostrich has little or no claw on the outer toe, while that of the third toe is toothed or serrated in a considerable number of Birds, but this is a character of very slight importance.

The covering of the metatarsus is usually "scutellated," but when the scutellae, or scales, which may be oblong or polygonal, are smaller than usual–and generally hexagonal–it is called reticulated. In some cases the surface becomes nearly or quite smooth ("ocreated" or "booted"), or more or less granulated.

8. The structure of the Skull is a study in itself and affords {11}considerable help in Taxonomy (Classification). It must suffice here to refer for the names of the parts to the subjoined figure.

The Bill, or Beak, is composed of an upper jaw or maxilla, and an under jaw or mandible. From the figure it will be seen that "maxilla" is not strictly the whole upper portion, though the term is thus used for convenience, as is the plural "mandibles" for the two jaws when mentioned simultaneously. The "rhamphotheca," or horny sheath, may be simple (undivided), or compound, that is, made of several distinct pieces. In the Anseres the covering is soft with a horny (corneous) tip or "nail"; in the Limicolae it varies extremely, producing a hard pickaxe, as in the Oystercatcher, or a delicate sensory organ as in the Snipe and Woodcock. The rhamphotheca at times has extraordinary outgrowths, as in the Hornbills, Sheathbills, and elsewhere. In the Accipitres, or Diurnal Birds of Prey, and most Psittaci, the base is soft and becomes a "cere," while the similar formation in the Columbae is due to a swelling of the operculum or covering of the nostrils. This operculum, moreover, may be leathery (coriaceous), as in the Charadriidae, Trochilidae and so forth, or rolled up, as in Rhinochetus; it may even result in a short soft tube, as in Caprimulgus, or in the hard double tube which gives the name of Tubinares to the Petrels. "Impervious" nostrils are those with a septum, or division, between the nasal cavities, "pervious" {12}those with none. The narrow slit-like or entirely closed nostrils of the Steganopodes should also be mentioned.

The form of the bill varies from the "spoon" of Platalea and Eurynorhynchus (spatulate) to the "arch" of Numenius, the scissors of Rhynchops, the "wedge" of Picus, the big rounded feature of the Psittaci, and so forth; but for details the characters of the several Families must be consulted, as also for helmets, shields, horns, knobs, and peculiarities due to the elongation, distorting or crossing of the mandibles. These, too, are often notched, serrated, lobed or "festooned," or emarginate (slightly indented); the curious transverse serrations or lamellae of the beak in Anseres, and the somewhat similar sifting apparatus in Phoenicopterus, Prion and Anastomus being especially remarkable. Teeth were probably lost by Birds before Tertiary times, but were possessed at least by Archaeopteryx, Hesperornis and Ichthyornis. The so-called "egg-tooth" of embryos is merely a calcareous protuberance on the upper surface of the bill, which is cast after being used to crack the shell.

9. The organs of deglutition and digestion begin with the tongue, which is subject to much variation of structure, according to the different groups of Birds, and is of course correlative with their habits. It has little connexion with taste, though often of assistance in obtaining nutriment. To this follows the gullet (oesophagus), which in many cases has an enlargement forming the crop (ingluvies), wherein the food may be temporarily retained before passing into the stomach, the last-named always having an antechamber (proventriculus) where digestion is largely accomplished, in front of the gizzard (ventriculus). This has frequently strong muscular walls, and its action is often assisted by the mechanical process of comminution performed by stones, grit or sand, swallowed for that purpose. The stomach is succeeded by the intestines, which in most cases have a pair of blind-sacs (caeca) attached to them, often acting as aids to digestion, though these are not always functional, and are absent in many Birds, while in others they attain a very large size, their condition being in consequence of some importance as a systematic character.

10. The organs of voice in Birds have long attracted special interest from the loud cries which some utter, and the melody with which others are gifted. Setting aside the part played by {13}the trachea or windpipe in supplying air to the lungs, its formation is worthy of attention. Its upper end consists of the larynx, and it passes down the neck as a flexible tube, formed by a continuous succession of bony rings connected by membrane, until it bifurcates into two bronchi, which open into the lungs. A common feature, found in many groups not nearly allied, is the dilatation of a portion, generally near the middle, while a remarkable modification is exhibited by the males of many of the Duck-tribe, some of the lowest rings being fused together and forming what is known as the bulla ossea or "labyrinth." In other Anatidae (some of the Swans), and some of the Cranes, the trachea enters the keel of the sternum; but a not unfrequent modification, usually confined to the male sex, often occurs elsewhere, when the windpipe is looped back upon itself. All these arrangements, however they may affect the sounds uttered by Birds, do not in themselves constitute the voice organ of most. That is reserved for the syrinx, a peculiarity of the Class Aves, consisting of the lower end of the trachea and the adjoining part of the bronchial tubes; and the varied modulations are effected by means of muscles attached thereto. These voice-muscles may be wholly absent or of the simplest character, but they attain their highest perfection in the Passeres, and especially in the large group of them known as Oscines, where there are often five or seven pairs. In this group the lowest four or five tracheal rings are solidly fused into a little bony box communicating with the bronchi; the first and second bronchial rings (or in this part often semi-rings) being closely attached to the trachea, and the spaces between the second and third and the third and fourth being generally closed by an outer tympaniform (drum-like) membrane, while the rest of the semi-rings of the bronchi are closed by the inner tympaniform membrane. It should be clearly understood that all the notes emitted by Birds are produced by the above structures only, and that the tongue has nothing to do with their utterance, except, possibly, in the case of the sounds that Parrots (but not other birds) are taught to produce.

Classification.–The Classification of Birds is still in a condition of uncertainty, notwithstanding the many schemes successively propounded during more than two centuries. To dwell upon them here would be impossible, and it is only practicable {14}to trace in the briefest way the line which has led to the most recent attempts, and to name those whose researches have produced the results which may be fairly regarded as attained. First among them is Nitzsch (1806-1840), to whom followed Merrem (1812-1817), and after a few years L'Herminier (1827). These three worked quite independently, and in their lifetime little notice was taken of their labours; for, though there were good ornithologists among their contemporaries, little value was then set upon internal characters in this connexion. An improvement took place when the great Johannes Müller (1846, 1847) published his scheme for grouping the Passeres, which, though based on purely anatomical facts, was almost immediately accepted, chiefly through the simultaneous exertions of Dr. Cabanis, by systematists of the Old School. For twenty years no advance was made, for the morphological researches of Parker were not directly taxonomical; but Huxley (1867, 1868) started what was practically a new line of investigation, though it subsequently appeared that up to a certain point it had been already suggested by Dr. Cornay (1842-1847). The impetus thus given was fortunately sustained, Huxley's example being followed by Dr. Murie, and by two promising men, A. Garrod and W. A. Forbes, both of whom died at an early age, leaving their mark in work which, though much of it was crude, was that of true genius. Mr. Sclater (1880) has tried to bring the results of the whole four into harmony with pre-existing views, and a similar attempt was that of Dr. Stejneger (1885); but all were overshadowed by the monumental performance of Prof. Fürbringer, whose Untersuchungen zur Morphologie und Systematik der Vögel, completed in 1888, must ever remain a record of unexampled labour, while his considerations on the derivation of Birds from Reptiles, and of the later groups of Birds from the earlier, whether his results be right or wrong, are of the utmost importance to the ornithologist. During the progress of this work the author was in frequent communication with Dr. Gadow, himself engaged on the ornithological portion of Bronn's Thier-Reich, and thus the opinions of each were in many cases mutually affected. Dr. Gadow, on the completion of his undertaking, propounded a scheme of classification, which is followed, with some slight modifications, in the present volume (see foregoing table)–it being, of course, understood that a linear arrangement is, {15}strictly speaking, impossible, since any group may have a decided affinity to more than two others. This Classification, beginning (as Birds themselves must have begun) with the lower forms, takes us, except in the Oscines, as far as the Families, which in most cases are fairly distinguishable, though of very variable value. Coming to Genera, and still more to Species, the opinions of authorities often differ so widely, that at present an attempt to reconcile them is hopeless. It cannot be denied that Genera and Species are merely "convenient bundles," and that divisions of either, if carried too far, defeat the object for which Classification is intended. Genera are only more distinct from Species, and Species from Races, because the intervening links have disappeared; and, if we could have before us the complete series which, according to the doctrine of Evolution, has at some time existed, neither Genus nor Species would be capable of definition, any more than are Races in many cases; while the same remark will apply to the larger groups.

From these Races or Geographical variations we may not unnaturally turn to Geographical Distribution. It will always be credited to Ornithology that the interesting study of the Geographical Distribution of Animals was first placed on a scientific basis as a result of the study of Birds. This was effected by Mr. Sclater, whose division of the Globe into Six "Regions"–the Palaearctic, Ethiopian, Indian, and Australian, forming one group–the "Old World" (Palaeogaea); and the Nearctic and Neotropical, forming a second–the "New World" (Neogaea); was announced in 1858 (J. Linn. Soc. ii. pp. 130-145). His scheme, being solely grounded on Ornithological considerations, was accepted with scarcely any modification by Mr. Wallace in his great work (Geograph. Distrib. of Animals, 1876), and by the majority of zoologists, though some demurred, and among them Huxley, who, in especial reference to Birds, shewed (Proc. Zool. Soc. 1868, pp. 313-319) that there was more reason to divide the earth's surface latitudinally than longitudinally, and that Four Regions were better than Six–these four being (1) Arctogaea, comprising Mr. Sclater's Indian, Ethiopian, Palaearctic, and Nearctic; (2) Austro-Columbia, corresponding with the Neotropical; (3) Australasia; and (4) New Zealand–the last three being combined as Notogaea. In 1882 Prof. Heilprin proposed to unite Mr. Sclater's Palaearctic and Nearctic under {16}the name of Triarctic; but in the next year (Nature, xxvii. p. 606) adopted for that union Prof. Newton's earlier term Holarctic. Some other general schemes have been promulgated, as those of M. Trouessart and Professor Möbius; but they have found little support, and with regard to the Class Aves, though certainly not with regard to other groups as Pisces, or Mollusca, what is practically the scheme of Mr. Sclater has met with acceptance, whether with or without the modifications proposed by Huxley and Professor Newton, there being really but two important points of difference–(1) the recognition of New Zealand as a distinct Region, and (2) the union of the Nearctic and Palaearctic areas into a single Region. It would be impossible here to set forth the arguments by which these views are maintained or contested, and it must suffice to trace briefly the outlines of the several districts. New Zealand, if admitted as a distinct Region, consists only of the islands so named, the smaller Chatham, Auckland, and Macquarie groups, Antipodes Island, Lord Howe's, Norfolk and Kermadec Islands. The Australian, if the preceding be cut off, will include Tasmania, all Australia, and the islands to the northward as far as what has been called "Wallace's Line" (between Lombok and Bali), Celebes, New Guinea, New Britain, and all the countless groups of tropical islands in the Pacific Ocean–except the Galapagos, which undoubtedly belong to the next Region. The Neotropical is made up of all South America, the Antilles and Central America, the only doubt being whether to draw the northern boundary so as to exclude or include Mexico, or even the southern part of the United States. To this naturally succeeds, but with an indefinite southern boundary, the Nearctic, comprising the whole of the rest of North America to the shores of the Polar Sea, with the addition of Greenland. Its north-western corner, Alaska, is now known to be largely tenanted by forms from Asia, not found elsewhere in America, and this is one of the chief reasons assigned for uniting it with the Palaearctic area, which may be taken to include Japan and all continental Asia to the north of China proper, the Himalayas, the Persian Gulf and the east end of the Mediterranean. Some authorities would add Northern Arabia and Lower Egypt; but all have agreed to include Tunis and the ancient Mauritania–the Barbary States lying north of the Great Desert to the Atlantic Ocean about Mogador, as well as the Canaries, Madeira and the Azores, with the whole of Europe {17}from Greece to Iceland. What is left of Arabia and Africa, after taking off the above portions, with the addition of Madagascar and the Mascarene Islands, is the Ethiopian Region; and all the rest of continental Asia, with the islands not included in the Australian Region, becomes the Indian, or, as it has lately been called, the Oriental. It would be quite impossible to enumerate here the various Sub-regions and Provinces into which these several Regions may be divided. The views of Mr. Wallace are set forth at length in his excellent work, those of Mr. Sclater in The Ibis for 1891, pp. 514-557, and those of Professor Newton in his Dictionary of Birds. Many writers would assign to Madagascar a higher rank than that of a Sub-region.

Migration.–Few peculiarities of Birds have excited more general interest than their seasonal Migration, which in many species is so marked as to have been observed from very remote times; and it is probable that nearly all species are subject to periodical movements of varying extent. These movements are greatest in the Birds which have their breeding quarters in the northern parts of the Northern Hemisphere; and, with some exceptions, it may be said that the more northerly is the range of a species the more extensive are its migratory wanderings. In the Southern Hemisphere the facts known are as yet insufficient to allow of safe deductions. Absence of a food-supply in winter is alone enough to account for migration in the above cases, and the return from the south in spring is probably due to the desire of Birds to reoccupy their old haunts, or those in which they have been bred. But just as there are some species which habitually breed within the Arctic Circle and winter in the Tropics, there are others which may not go so far in either direction, and yet have their movements governed by exactly the same principle, with the result that in a temperate zone we have Birds coming from the north to winter with us, while others, arriving from the south in spring, spend the summer here, and depart towards autumn. Others again, the true "Birds of Passage," arriving like the last in spring, make little or no stay, but pass onward to more northerly lands, and re-appear for as short a time in autumn on their return journey southwards. Moreover, observation shews that, in most parts of the temperate zone, there are many Birds which, though resident as species, are migratory as individuals–that is to say, that while examples of {18}the species may be met with at certain spots throughout the whole year, those which occur at one season are not always the same individuals as those which occur at another–the particular Thrush, Titmouse, or Finch, appearing in the winter not being identical with that which appears in summer. Again, among species of which some individuals are constantly present throughout the year, a great accession to the numbers is made at the close of the breeding-season by the influx of other individuals of the same species bred in another district, though this influx generally lasts for a comparatively short time, and the strangers pass on, accompanied it may be, by some or even most of those that have been reared on the spot in the season immediately preceding. These species are the "Partial Migrants."

It would at first seem from the above that the annual migratory movement would be in a direction due north and south, or south and north, according to season, and so in a general way it is; but there is no doubt that this simple movement is disturbed by many causes, chief among which is possibly the configuration of the land, which is found to give rise to considerable deviations, and that to an extent which is at present very imperfectly understood. It may be considered proved that the trend of a coast-line, the course of a great river, or the intervention of a chain of mountains, has a very appreciable effect on the direction taken by migrating Birds; but not one of these, nor all in combination, affords a sufficient explanation of all the deflexions, and will certainly not account for at least one remarkable fact, as it may now be regarded–the tendency of many Birds in Eastern Europe and part of Siberia to travel westward towards the close of summer or in autumn. This is shewn in several ways, but in none better than by the almost yearly occurrence in Britain at that season of examples of species which breed only in the Russian Empire. For, admitting that such examples are stray wanderers, which have lost their course, their appearance here is still useful in indicating the existence of the westward movement; and, with the evidence they furnish before us, we may judge whence come vast numbers of others–Starlings, Crows, Rooks, Jays, Larks, and what not, whose origin and starting-point it would be otherwise hard to trace or even surmise. Much has been written, especially in Europe, on so-called Lines of Flight, but as yet to little purpose, and indeed {19}scarcely any writers on the subject have had sufficient data to form an hypothesis, so that it is not surprising that hardly any two agree in theory.^[10] In other parts of the world there is still less ground for theorising, though in North America many valuable observations have been made; and these, in conjunction with those carried on in Europe, will no doubt in due time lead to satisfactory results as regards the Northern Hemisphere. Concerning the Southern our ignorance is almost complete.

Of the way in which Migration is performed there is still much to learn–but one thing is certain, all Birds do not migrate in the same manner. Some gather in flocks, great or small, others seem to accomplish their northward journey in pairs, or at any-rate arrive at their breeding-quarters already paired. Some undoubtedly voyage by night, others may be seen to travel by day. Of the Birds which in spring arrive unpaired, it is now incontestable that the males outstrip or precede the females. There is, moreover, equal diversity in the southward movements towards the close of summer and all through the autumn. Of some species the earlier broods disappear without attracting attention, and the later broods as well as the parents slip away almost as imperceptibly. In one remarkable case, that of the Cuckoo, the adults leave this country long before the young are fit to follow; but, in by far the greater number, the young start first, and are followed, often at an interval of some weeks, by their parents.^[11] It is contended by many that of actual Migration we see very little, since it is constantly carried on at a height where the Birds are beyond our ordinary observation, and as regards some species this seems to be true. Moreover, it would seem that the longest flights are performed by night, and when the sky is clear, so that only in thick weather do the Birds come near enough to the earth to be heard–seeing them being of course impossible in the dark, though in a few cases they have been telescopically observed passing across the face of the moon. It is certain that many of the smaller land-birds gradually press {20}onwards prior to leaving our shores, but after that they may possibly betake themselves aloft to continue their journey.

The speed at which Birds travel during Migration is a matter on which very diverse opinions have been and are held; but the highest estimates, such as those of the late Herr Gätke (who would allow even 150 miles an hour), can scarcely be otherwise than exaggerations; for there is no evidence of any but exceptional performances at such rates, and there is really no reason to suppose that Birds can fly faster at a higher elevation than at a lower.

Terminology.–The annexed figure explains the nomenclature of most of the outward parts of a Bird, but some further explanations may be given, as below:–

ARCHAEORNITHES–NEORNITHES RATITAE–NEORNITHES ODONTOLCAE.

The Class AVES is divided by Dr. Gadow (Bronn's Klassen und Ordnungen des Thier-Reichs, Aves, Systemat. Theil, p. 299) into two Sub-classes of like value, ARCHAEORNITHES and NEORNITHES, though some writers prefer to consider the former as of equal rank only to the several subdivisions of the latter here adopted, namely, Ratitae, Odontolcae, and Carinatae (p. 25). The question is clearly one of degree, and depends entirely on the amount of weight assigned to the various points of distinction to be mentioned below.

The Sub-class ARCHAEORNITHES is at present represented by but one member, the first undoubted fossil Bird, made known in 1861 by Andreas Wagner from the Jurassic slate formation of Solenhofen in Bavaria, and now preserved in the British Museum. This he described under the name of Griphosaurus; but as Hermann von Meyer had already bestowed the title of Archaeopteryx lithographica upon a bird, presumably identical, a feather of which had been obtained from the above system, the latter appellation has a prior claim. In 1877 a second example, now at Berlin, was procured from the same beds,^[12] since which date Meyer's specific name has become firmly established, in place of that of macrura given by Owen to Wagner's specimen.

This very remarkable animal, about the size of a Rook, is without doubt a connecting link between Reptiles and Birds; but zoologists are practically unanimous in regarding it as an Avine form, with Reptilian affinities and probably arboreal habits.

The sternum was possibly furnished with a weak keel, the strong wide furcula was U-shaped, the ribs had no uncinate processes, while in all probability the coracoid and scapula made a right, or even an acute, angle at their junction, and the centra of the vertebrae of the neck and back were biconcave. The bill was short and blunt, each side of the upper jaw possessing about thirteen teeth, of which six seem to have belonged to the praemaxilla; whereas in each side of the lower jaw only three can be recognised, and those towards the anterior extremity. These teeth, conical in shape and of fairly equal size, were fixed in a regular row, in distinct sockets. The fibula and tibia did not coalesce, the latter exceeding the metatarsus in length; the toes were four {25}in number, with two, three, four, and five phalanges respectively, ending in claws, the hallux being directed backwards. The manus had three free digits, and apparently three free metacarpals; the pollex consisted of two joints, the index of three and the third finger of four, while each had a strong hooked claw at the tip. The hand was furnished with six or seven well-developed primaries, attached to the third metacarpal and the second and third digits, the number of secondaries being ten. The long Lizard-like tail had no terminal pygostyle, but was composed of about twenty-one free post-sacral vertebrae, of which the first twelve each bore a pair of large feathers, similar to those of the wing, with the inner webs broader than the outer, and with decided shafts.^[13]

The Sub-class NEORNITHES may be arranged, as above stated, in three divisions, (A) Neornithes Ratitae, (B) Neornithes Odontolcae, and (C) Neornithes Carinatae. The first of these contains the Ratite Birds proper and possibly part of the so-called Stereornithes of Patagonia (p. 43), with several fossil forms of doubtful position from England, France, and New Mexico, as will be seen below; the second the Hesperornithes of the Cretaceous Shales of Kansas, the Enaliornithes of the Cambridge Upper Greensand, and Baptornis of the American Chalk; the third the Ichthyornithes of the aforesaid Kansas deposits, and all other existing Birds, with various extinct species closely allied to them.

Of the points of distinction between the Neornithes and the Archaeornithes the most important are that the metacarpals are fused together, the second digit being the longest, and the third more or less reduced; and that the number of caudal vertebrae does not, as far as is known, exceed thirteen, of which the last five or six combine together to form a pygostyle, except in the Hesperornithes, Ratitae, and Tinamidae, where such is seldom the case.^[14] The centra of the vertebrae also are concave on one side only, except in Ichthyornis, and perhaps in Enaliornis. The possession of teeth is, of course, exceptional, as is the remarkable loss of the keel of the sternum in the Ratitae.

It is now generally, if not universally, agreed that Flightless Birds were developed from those that could fly. It does not, however, necessarily follow that the Neornithes are direct {26}descendants of the Archaeornithes, as each may be a separate offshoot from the same parent stem. All we can safely assert is, that the former were in existence about the end of the Jurassic times, that teeth were still retained in some cases during the Cretaceous Epoch, and that not only normal forms, but also flightless forms without keel or pygostyle,^[15] had arisen by that date.

(A) The Ratitae are commonly characterised as Birds with no keel to the sternum; but this will not hold as a definition, since Hesperornis has also that peculiarity, while such genera as Didus, Stringops, Cnemiornis, and Notornis are nearly in the same condition. It is no one point, therefore, but the sum of many, which enables us to draw so clear a line of demarcation between this primitive group and the remainder of existing forms; nevertheless it is convenient to preserve the name unaltered, as it is well understood to what members of the class it is more especially meant to apply. The rhamphotheca, or horny sheath of the bill, instead of being simple, is composed of several more or less separate pieces, as in the Procellariidae, Tinamidae, and Steganopodes; the quadrate bone, by means of which the lower jaw is articulated to the skull, in place of two proximal knobs has only one, as in Hesperornis, Ichthyornis, and the Tinamidae; the coracoid and scapula are fused together, and meet at an obtuse, as opposed to an acute or right, angle; and the last six or seven caudal vertebrae do not coalesce into a pygostyle, or upright triangular expansion to carry the rectrices, a state of things found elsewhere in Hesperornis and the Tinamidae.^[16] The reduced wings preclude flight; the tail is functionless, as in the Podicipedidae and Tinamidae; the tongue is very small; the oil gland is absent; the penis is large and erectile, being comparable to that of the Anseriformes; while in the adult the feathers are evenly distributed over the whole surface, as in the Spheniscidae and Palamedeidae, no down being present. Claws are found on the pollex and index in Struthio and Rhea, or occasionally on the third digit; in Casuarius, Dromaeus, and Apteryx they occur only on the index.

Ratite Birds proper are comprised in six groups, Struthiones or Ostriches, Rheae or Nandus, Megistanes or Cassowaries and Emeus, Apteryges or Kiwis, Dinornithes or Moas, and Aepyornithes or Rocs.

I. STRUTHIONES.

Fam. Struthionidae.–These birds are distinguished from all others by having only two toes–the third and fourth–the terminal phalanges of which are shortened and bear thick stunted claws, that of the outer toe being commonly absent. The whole foot, including the long scutellated metatarsus, is exceptionally stout, and the toes are padded beneath. The beak is short, broad, and depressed, with deeply split gape; the head is small, with large eyes; the neck very long; the wing- and drooping tail-feathers–the plumes of commerce–are large and soft, with broad equal vanes. The furcula and syringeal muscles are wanting, nor is there any aftershaft.

Struthio camelus, the Ostrich or "Camel-bird" of North Africa, now extends from Barbary to Arabia, and even to Mesopotamia, though no longer found, as of old, in Egypt or Central Asia, its former occurrence in Baluchistan being somewhat open to question. It is black with white wings and tail, having a flesh-coloured neck covered with brownish down, and partially bare tibiae of the same hue. The female and young male are almost entirely cinereous, while the chicks are clothed with bristly yellowish-white down with blackish stripes. The eggs of the typical northern bird have a surface like ivory, while those from Southern Africa are marked with close-set pits, whence some authorities recognise a different species (S. australis) in the latter region, distinguishable, moreover, by the bluish colour of the naked parts. Examples from Somaliland and the adjoining districts of East Africa to Lake Tanganyika are separated as S. molybdophanes, on account of the leaden colour of the unfeathered portions, coupled with a red patch on the front of the metatarsus. The eggs are smoother than in the southern species, but similarly pitted. The fossil forms S. asiaticus from the Pliocene of the Siwalik Hills of India, and S. karatheodori from the Upper Miocene of Samos complete the family, while S. (Struthiolithus) chersonensis has been founded on a petrified egg from the government of Cherson in South Russia.

The Ostrich stands about eight feet high, being the largest of existing birds; it frequents sandy wastes and dry arid localities, such as are found in the Sahara and the plains and valleys of Southern Africa, while districts studded with low bushes are not unfrequently tenanted. Though the fable of the head being hidden to avoid detection is of course devoid of foundation, this species is timid and wild in its native haunts, and being keen-sighted as well as wary, gives an impression of great restlessness. From the fact that a single stride is said to cover twenty-five feet or more, it will readily be understood that the speed is very great, exceeding that of a galloping horse; but, owing to its habit of running in a curve, it is generally possible to intercept the bird's path at a distance from the point where it started. In motion the head is held forward, and the wings are outspread, while both beak and feet are used as weapons of defence when capture is imminent, the latter delivering strong sideways kicks, which make close quarters very dangerous. Forty or fifty individuals may at times be seen in company; the usual parties, however, consist of five or six at most, especially during the breeding season, when the polygamous cock escorts a flock of several hens, obtained by battle or allured by courting performances earlier in the season. A liking for the companionship of zebras, hartebeests and other antelopes, has been noticed by various observers. The cry is said to be hoarse and mournful, resembling the roar of a lion or {29}the lowing of an ox; but Ostriches are, as a rule, decidedly silent. In a state of nature the food consists chiefly of herbage, including seeds and fruits; in captivity the diet is of every description, and even in a wild condition small mammals, birds, reptiles, and insects are eaten, with a quantity of grit to aid digestion. In confinement the birds become very tame, and will then swallow bones, nails, and the like–in fact almost anything they can pick up. They can exist for a long time without water, but drink regularly when opportunity offers; they show a liking for salt, and will bathe in the sea or in rivers, immersed up to the neck. The hens belonging to one cock lay in the same nest, which is a fairly shallow excavation dug in sand or dry soil, and surrounded by the material thrown out during the process, or more rarely by an edging of grass. The spot is hard to discover in the desert, the stride being too long for tracks to be of much assistance. More than thirty yellowish-white eggs are sometimes deposited within the pit in circular arrangement, and many more are dropped around, to serve, it is asserted, for food for the newly-hatched young; in the wild state, however, the average number is probably less. The contents, equal to those of some two dozen hens' eggs, are used for food by the natives, the shells forming convenient pots for water and so forth. The cock undertakes almost the whole duty of incubation, being occasionally relieved by the hens during the daytime;^[17] but when the sun is hot no brooding is necessary, though a covering of sand is superposed to guard the spot from the depredations of marauders. The chicks, which run from the shell, are hatched in six or seven weeks, and are accompanied by both parents, the male often counterfeiting wounds to draw away the intruder, circling around with drooping wings or throwing himself down as if in extremities.

Ostriches were well known to the ancients, who used the plumes for ornament, as we do; these were considered emblems of justice from the equality of the two webs, or were worn in token of victory, as is still done in some parts of Africa. The words of Aristotle–who was followed by Pliny in the statement that the Ostrich was part quadruped, part bird–combine with those of Xenophon to bear witness to this knowledge, while monuments, inscriptions, and even the Bible tell the same tale. In the Sahara and elsewhere these birds are hunted with horses and camels, {30}being stalked or ridden down by means of fresh relays of beasts; the Namaquas draw a cordon round them; the Bushman, concealed in sand or disguised in skins, shoots them with poisoned arrows; while the lasso, pitfall, or other device are used in particular districts. Space will not permit a detailed account of the Ostrich farms of modern Africa, so well described in Messrs. de Mosenthal and Harting's Ostriches and Ostrich-Farming, and other books; but it may be mentioned that the tribes of the north of that continent have long been in the habit of domesticating the bird, that the value of the sales in South Africa is not far from a million pounds yearly, and that the plumes are plucked or, preferably, cut about twice a year, the adults yielding the finest feathers. The flesh is coarse, and of little use for food.

II. RHEAE.

Fam. Rheidae.–The Rheas, or Nandus, have the head, neck, and bill much like those of Ostriches, the maxilla being somewhat more rounded and terminating in a nail-like process; the metatarsus is also similar and equally stout in proportion, but the toes are three in number in place of two, the mid-phalanges being shortened and the terminal furnished with decided claws. In Rhea darwini alone the metatarsi are mainly reticulated instead of scutellated anteriorly, and have the upper portion feathered. The bones of the wing are comparatively well developed, the feathers being slender but not ornamental, while there is no apparent tail. The furcula is wanting, as is the aftershaft to the feathers, but the syrinx is tracheo-bronchial with one pair of syringeal muscles, a condition absolutely unique among the Ratitae. The head and neck are feathered, only the lores, orbits, and ear-openings being naked, and of these the latter are surrounded by bristles.

Rhea americana, the so-called American Ostrich, the Ema of the Brazilians, the Avestruz, Nandú, or Chueké of Argentina, is found from Bolivia, Paraguay, and South Brazil to the Rio Negro, if not further; it is brownish-grey with blackish crown, nape, and breast, white thighs and abdomen, and yellowish neck. The sub-species R. macrorhyncha of North-East Brazil is darker, with longer bill and more slender metatarsi. R. darwini, which occurs south of the Rio Negro, and up the Andes to Tarapaca, is buffish-brown, with whiter underparts and white margins to the {31}feathers of the wings and back. Hens are not so dark, and Mr. Hudson says^[18] that in R. darwini the young are dusky grey and are hatched with the legs feathered to the toes. Rheas are shorter than Ostriches by about a couple of feet, R. americana being the largest form; the feathers are much rounded, broad, and very soft. Fossil remains occur in the Upper Tertiary or quite recent deposits of South America.

The members of this family find their favourite haunts on the treeless flats of the Argentine pampas, the scrub-covered plains of Patagonia, or the dry open Sertões of Brazil, where their acute vision enables them to detect the approach of enemies from afar. Small flocks of from three to seven individuals are met with at certain seasons, and parties of twenty or thirty at other times–often with deer or guanacos–so it would appear that, as in the case of the Ostrich, larger companies are formed after the young are able to provide for themselves. The birds become exceedingly tame when not molested, but when danger threatens they run at great speed, doubling upon their pursuers constantly, or crouching down among bushes or other cover, if they think they can escape observation. In the latter case they will lie closely until almost trodden upon, and may be shot before they rise by the hunter who cautiously approaches their hiding-place, as the head is usually visible above the surrounding vegetation. When moving at full pace the wings have normally a somewhat drooping position, but they are raised alternately above the back–apparently {32}to aid progress–when fresh exertions are necessary. Mr. Hudson tells us^[19] that Darwin's Rhea "carries its neck stretched forward, which makes it seem lower in stature than the allied species." The diet consists chiefly of grass, roots, and seeds, but berries of Empetrum are a favourite food, and lizards, insects, worms, and molluscs are said to be eaten, together with hard substances to promote digestion. Nandus take readily to the water, and can swim across a river several hundred yards wide, the body being hardly visible. In spring the cock utters a deep, resonant, booming noise, a loud hiss being not uncommonly heard also; while at that season the rival males attack each other viciously with their beaks, trampling down the ground in their passion, but not generally using their feet, as they do when wounded. The hens secured by each of the cocks lay together in a mere depression in the soil with very little, if any, lining; the eggs numbering from twenty to thirty, or exceptionally more, besides those scattered about outside the nest. Here again Mr. Hudson is our authority for stating^[20] that the eggs of R. americana are golden yellow when fresh, those of R. darwini deep rich green; both however fade quickly to a whitish colour. The male incubates very closely for about six weeks, often taking up his position, as the Ostrich does, before the final egg is laid; he afterwards attends upon the young, and charges intruders who seem dangerous, with outstretched wings and beak. Rheas may be captured by riding after them in a semicircle, which closes upon them as they go, or by means of long-winded hounds; but the most usual method is that of hurling the "bolas" or leaden balls connected by leather thongs, which wind around the bird's neck or legs, and thereby hamper its movements or throw it down. The feathers, though inferior to Ostrich plumes, are much used for brooms and the like, and are said to be called "Vautour" in the trade. The flesh is very poor. These birds have bred both on the Continent and in Britain.

III. MEGISTANES.

The Megistanes comprise the Casuariidae or Cassowaries, and the Dromaeidae or Emeus, the following being the chief peculiarities of the group. The wings are quite rudimentary; {33}the aftershaft of the contour feathers is extremely large, so that they appear to be double; three front toes are present, with shortened mid-phalanges and large claws; and the two clavicles do not meet. The lack of ornamental wing- or tail-plumes, and the hair-like nature of the coat is also characteristic, while, as opposed to Rhea, there is no indication of syringeal muscles. Within the group itself the Cassowaries are distinguished from the Emeus by the points next to be mentioned. The former have a compressed keeled beak and a large casque of bony tissue upon the bare head, the greater part of the neck being also naked and in most cases wattled; the remiges are reduced to thick black barbless quills from four to six in number, and the inner toe has a particularly long sharp claw. Emeus, on the contrary, have a broad depressed beak, short feathers on the head and neck, no helmet, wattles, or spines on the wing, and an ordinary claw on the inner toe. Both Families have long necks, stout metatarsi covered with coarse roundish scales, and toes padded below; the tibia being nearly, if not quite, covered by the plumage.

Fam. I. Casuariidae.–Following Professor Salvadori,^[21] Cassowaries may be divided into two groups: the first with the helmet laterally compressed, and the second where it is triangular and pyramidal, or even depressed. They are all large birds, though smaller than Emeus, which are only surpassed in size among existing forms by the Ostrich; the colour of the coarse but glossy hair-like plumage is black, and similar in both sexes; the hen is bigger than the cock, as is also the case in the Dromaeidae and Apterygidae.

Of the first of the above groups, Casuarius tricarunculatus, from Warbusi in New Guinea, which is possibly a "sport," has two lateral wattles on the fore-neck and a third small median caruncle at a lower level. C. bicarunculatus, of the Aru Islands, has two long distant reddish-violet wattles, a black casque, bluish-green head, and blue neck with some red behind. C. galeatus of Ceram, the species first known to ornithologists, is similarly coloured, though less brightly, and has the flesh-coloured throat-wattles close together, and a naked reddish-purple space on each side of the neck. The larger C. australis of North-East Australia has a higher helmet, a brighter blue throat, and a few scattered hairs on the wattles, which Wall, who discovered the species, said were coloured with blue and scarlet. C. beccarii of the Aru Islands, {34}Middle and South New Guinea, has the front and top of the casque black, its sides greenish, and its back yellowish; the head is grey-blue, the throat and sides of the neck are blue, the hind-neck is red and orange, a yellow streak running across to the mandible; a bare space on each side of the base of the neck is flesh-coloured, and the long single neck-wattle of the same colour is somewhat deeply divided at the tip.

Of the second group, C. uniappendiculatus (Fig. 10), of Salawatti and the adjoining parts of New Guinea, has the head, throat, and nape blue, the lower portion of the neck and the median pear-shaped caruncle yellow, the casque dusky olive, and a longitudinal naked space towards the sides of the neck flesh-coloured with a yellow margin. C. occipitalis of Jobi Island is distinguished from the last-named by a large occipital spot of yellow and a paler helmet; while the remaining three forms have no wattle at all. Of these, C. papuanus, of North-East New Guinea, has a dusky black casque, blue head, throat, and fore-neck, grey-green occiput and auricular region, and orange hind-neck changing into rosy flesh-colour towards the sides. C. picticollis of South-East New Guinea has a black helmet, grey-blue occiput, violet-blue nape, pale blue hind-neck, red throat and longitudinal space on the sides of the lower neck; C. bennetti of New Britain differing in having the head and neck of an almost uniform blue. Nestling Cassowaries are clothed in rusty brown, relieved by darker stripes; at a later period they become more tawny, and the black plumage begins to appear; but a few hair-like feathers remain on the head for some time, while the helmet is very gradually developed from a flat Coot-like shield, though the gaudy colours of the neck and wattles are assumed much earlier.^[22]

All the species of this family inhabit wooded country, commonly of the densest description, though often found in more open scrub and in the neighbourhood of creeks and watercourses. Naturally shy but inquisitive, they have been rendered doubly wary by man's persecution since their haunts have been invaded by colonists. They dislike the sun, and emerge from cover only in the morning and evening, seeking their favourite spots, where they feed chiefly on fallen fruit, varying this diet with insects and crustaceans. Berries, leaf-buds, and bulbs are, however, also eaten, with grit and pebbles for digestive purposes, and in captivity they are almost omnivorous.

In this state they become extremely tame, and are kept like fowls by the natives of some districts, who consider the flesh very palatable; while in Queensland the adults are said to be hunted with dogs. The plumage is used for the manufacture of mats, rugs, head-ornaments, and the like. Cassowaries run with wonderful swiftness, though rather heavily, diving into the bushes at a moment's notice, or aiding themselves by their wings, and leaping over obstacles as much as six feet high, if shelter is not readily available. They usually rest on the whole of the metatarsus, but sleep on the breast, or perhaps occasionally on the side; at other times they will dance about with contortions of the neck, or roll on the ground like playful monkeys. Old males become very fierce when driven to bay, kicking out in front or sideways, ruffling up their feathers and using their beaks at the same time. In the wet season swimming is a common practice, wide rivers being {36}crossed with ease, and in the absence of other bathing-places the sea is often utilised. The note in a state of excitement is a sort of grunt or snort, the call to the young being of a lowing nature; but the ordinary voice is loud, guttural, and unearthly, consisting of quickly-repeated croaking sounds, lasting for as long as three minutes, and audible at a distance of a mile, or considerably more. The female is much quieter, while the "Mooruk" (C. bennetti) is stated to utter a low scolding or plaintive whistle. A rough nest of leaves and grass is formed in a depression of the soil, generally below bushes or tangled undergrowth, in which from three to six very large eggs are deposited, placed in the shape of the letter V. These are normally light green in ground colour, with close-set granulations of dark bright green; but one, if not more, is ordinarily of a perfectly smooth texture, and is therefore entirely light green. The cock incubates, it appears, solely, though some say that the hen takes her turn; and the former tends the young when hatched, the period of sitting being about seven weeks. The nest is said to be covered by the parent if left for a time, but this is uncertain, as is the use of the two or three eggs scattered round the nest, which are asserted by natives of widely-distant districts to furnish food for the chicks. After breeding, small flocks are formed in some cases, possibly by the combination of two families. The Ceram species, which seems to have been called "Emeu" or "Ema" by the early Portuguese navigators, often lays in captivity, while C. bennetti has bred in the gardens of the Zoological Society of London.

Fossil remains occur in Australia. Hypselornis sivalensis is an allied form from the Pliocene of the Siwalik Hills in India.

Fam. II. Dromaeidae.–From about the beginning of this century the name "Emeu," used, as mentioned above, in varying form for both the Rhea and the Cassowary, has been restricted to the genus Dromaeus, the members of which stand more than five feet high, though lower on their legs than an Ostrich. D. novae-hollandiae of the interior of Eastern Australia, which extended in times past to Tasmania and the islands in Bass's Straits, is blackish grey, with black tips to the plumage. D. irroratus, a more slender species from West, and probably the adjoining parts of South, Australia, has each feather transversely barred with dark grey and white, and a rufous margin to the black patch at the end. Young birds in down are greyish-white, with longitudinal blackish streaks above, {37}and spots on the head and lower parts. The sexes are similarly coloured, both possessing a remarkable tracheal pouch, connected by a slit with the windpipe, and only fully developed in adults.^[23]

In their general habits Emeus are not unlike Cassowaries, but they inhabit sandy plains or open forest districts, being invariably monogamous, though seen in small parties after breeding. Their sight is keen, they run strongly and rapidly, rest on the whole metatarsus, and kick out backwards towards the side. The food is of fruit, roots, and herbage, generally obtained in the morning or evening; water is freely drunk, and the birds love bathing, being capable of crossing even a broad river. They utter at times a hissing or grunting sound, but in the nesting season a peculiar loud booming or drumming note is produced, probably in connexion with the tracheal pouch. The nest may be a mere hollow scraped in the ground, with or without a surrounding ring of grass or plant-stems, or a mound of bark-scales some three inches high^[24]; the eggs are from seven to thirteen in number, or even more, and are of a dark, or occasionally light, {38}green colour, while the surface is covered with granulations which give it the appearance of shagreen. They are small for the size of the bird, being less than those of the Cassowary. The cock performs the duties of incubation, and it is very doubtful whether the hen ever assists him; the chicks break the shell in about eight weeks. The flesh is moderately good for eating, and the fat below the skin yields a large quantity of oil. The birds are constantly hunted with dogs or shot on account of the damage they do to wire fencing and the grass they devour. Emeus are easily domesticated, and propagate readily in semi-confinement, being perfectly hardy in Britain and elsewhere.

D. patricius is a fossil species from the Pleistocene of Queensland and New South Wales. D. gracilipes is another extinct Australian form, but Dromornis australis of Queensland may indicate a distinct group of Ratitae.^[25] Dromaeus ater, of Kangaroo Island, off the south coast of Australia, is now extinct, though a stuffed skin and a skeleton are in the Paris Museum.^[26]

IV. APTERYGES.

The Apteryges, or Kiwis, have been recently shown to be much more nearly related to the Dinornithes than to the remaining Ratite forms, and are accordingly placed in close proximity to them in the classification here adopted. Professor T. J. Parker has, moreover, lately formulated a new system–excluding the Aepyornithes, which may commend itself to many persons as a further improvement.^[27] In this, the Order Struthiones contains the family Struthionidae, and the Rheae the Rheidae; but the third Order, upon which the name Megistanes, Vieillot, is bestowed, includes two Sub-Orders–Casuariformes, comprising the Casuariidae and Dromaeidae, and Apterygiformes, with the Dinornithidae and Apterygidae. In other words, the original stock is considered to have produced three Ratite branches only, the third of which gives rise to two twigs, each of these separating again into two smaller twigs representing the Families.

Fam. Apterygidae.–These birds are at once distinguished {39}from all their allies by their small size, and by the long, weak, decurved bill, which tapers regularly and has the nostrils placed almost at the extremity. The head and eyes are comparatively small, as will be seen to be the case in the Dinornithidae. The legs are very stout and situated backwardly, a small elevated hallux is present, and the toes are provided with long, sharp claws. The moderate metatarsus is reticulated in the young, but is clothed with fairly large scutes in the adult, when it becomes much smoother. The wings are small-boned and invisible, with functionless quills, the tail is rudimentary, the aftershaft and furcula are absent, while many elongated hairs occur on the front of the head.

These curious flightless birds are confined to New Zealand, whence a specimen was brought to England as early as 1813. Apteryx mantelli, of the North Island, is deep red-brown with longitudinal streaks of yellowish-brown, the head being darker and the lower parts greyer; A. australis, of the South Island, is lighter, and feels soft instead of harsh when grasped. A. oweni, of both islands, is much smaller, and is light grey-brown, transversely marked with blackish bars. A. haasti, also said to occur in both islands,^[28] is a larger and darker form of the last named; A. lawryi, of Stewart Island, hardly differs from A. australis; while A. maximus, of Verreaux, is a very doubtful species. Mr. Rothschild^[29] has founded a sub-species (occidentalis) {40}on examples of A. oweni from the North Island and the west of the South Island. In all these birds the lanceolate feathers have a hair-like texture, due to the disunited filaments of the upper portion, the lower part being covered with grey down, and the rhachis more or less exserted. The tibia is feathered, the bill being yellowish, and the feet brown or black. The female is similar, but larger, the young blacker. Mr. Lydekker has described a fossil species, Pseudapteryx gracilis, from New Zealand,^[30] and Mr. De Vis Metapteryx bifrons from Queensland.^[31]

Kiwis inhabit wooded country and hills up to the snow line; they are still met with at low elevations on a few islands, but their retreats are now chiefly on the slopes and in the gullies of the mountains, where a dense undergrowth of shrubs and tree-ferns shades a carpet of creeping vegetation and moss. Here parties of from six to twelve used to be seen, though in the breeding season they separated into pairs, but at the present day flocks can hardly be hoped for. In the daytime these shy birds hide in burrows in the ground, or natural cavities under tree-roots or rocks, while towards dusk they emerge in an animated condition. The direct rays of the sun seem to dazzle them, and they roll themselves up into a ball, if not disturbed; when stirred up they are somewhat sleepy and quickly retreat to cover. Lengthy strides carry them along at a great pace, the body being held obliquely with outstretched neck; and, if molested, they ruffle up the plumage and snap the bill, while striking viciously with their feet at the intruder, the leg being drawn up to the breast and the blow delivered downwards. Sometimes they rest upright with the point of the bill touching the ground, sometimes upon the whole metatarsus, but usually they are seen at feeding time cautiously moving from spot to spot, and tapping the soil or the walls of their cage with their long sensitive beaks. A sniffing sound accompanies this operation, and probably the smell of food assists in its discovery, yet the sense of touch is no doubt the primary agent. The diet consists chiefly of worms, in search of which the ground is deeply probed, and shows funnel-like holes scattered over its surface; when a capture is made the worm is extricated with a gentle wriggling motion, and is either beaten upon the ground to kill it, or swallowed at once with a jerk of {41}the head. Grubs, beetles, molluscs, and berries are also eaten, with grit or pebbles as digestives. The loud whistling note, which gives the name to the Kiwi, is chiefly heard on light nights, that of the female being shorter, and the young uttering a chuckling or kitten-like cry. Growls are emitted by the birds when disturbed, and they have a curious way of yawning in the daytime. The nest is usually in an enlarged space at the end of a round tunnel in the soft earth, said to be made by the female alone, the opening being under a tree-root, a stone, or a tussock of grass; it consists merely of a little dry fern, herbage, or a few leaves. The eggs–generally two in number, though one is often found, and three are recorded–are enormous for the size of the bird, and are equal to a quarter of its weight; they are pure white, or slightly green in hue, with a smooth surface, recalling by their appearance those of the Whooper. The Maories are very fond of the flesh, either roasted or boiled, and hunt Kiwis systematically with muzzled dogs, while of old the chiefs utilised the plumage for ornamentation. The cock performs most, if not all, of the duties of incubation, and attends upon the young. Females lay in captivity, but no chicks appear to have been hatched as yet under these conditions.

V. DINORNITHES.

The Family Dinornithidae contains those well-known extinct New Zealand forms the Moas, as they are supposed to have been denominated by the Maories, some of which were of gigantic size. The larger species must have been comparatively rare, judging by the fossils obtained, while some seem to have survived until about four or five hundred years ago, or even a century later in the South Island. Being flightless, these birds were easily slaughtered by the natives, who were very fond of the flesh, and captured them when exhausted by repeated spear-wounds, after they had been driven from their retreats by burning the grass and vegetation. It was not until the year 1839 that a femur-shaft was exhibited by Owen to the Zoological Society of London, that being the first portion of a Moa known to have reached this country; but since the above date an immense quantity of bones of all descriptions have been procured in many parts of both the North and the South Islands, some hidden under the sand or exposed upon {42}its surface, some in marshes and superficial deposits generally, and others in caves, hollows of rocks, or cooking places of the former inhabitants. Footprints have been observed in the sandstone; portions of muscles, ligaments, and even of skin have been discovered; and, most remarkable of all, feathers have been met with of fresh appearance and unfaded colours. Pebbles used to aid digestion, and eggs, both whole and fragmentary, complete the list.

Moas had comparatively small heads, and also small orbits and eyes; the bill varied, as will be seen below; the legs were stout, though not always equally so, a hallux being usually present; the wings were extremely reduced, or even wanting; the furcula was absent, and the aftershaft of the larger feathers was of great size. The neck is supposed to have been partially bare, while the webs of the rounded feathers were disunited and more or less downy below. Some of the latter were black, with red-brown bases and white tips, others were blackish-brown or yellowish.

Professor Parker, in his recent memoir,^[32] proposes three Sub-families, Dinornithinae, Anomalopteryginae, and Emeinae; Megalapteryx, which he omits, possibly representing a fourth. The first of these contains only one genus, Dinornis, with wide convex sternum, comparatively slender limbs, broad skull, and long, wide, deflected beak; the height of D. maximus, the largest of the whole group, being estimated at about twelve feet. The second Sub-family comprises three genera, Pachyornis, Mesopteryx, and Anomalopteryx, forms of small or moderate height and varying bulk, with less broad skulls and pointed beaks, the sternum ranging from long and narrow to wide and flat. The third possesses a single genus, Emeus, in which the limbs are heavy, the strongly-built skull is narrow, and the beak short and broad. Pachyornis elephantopus has extraordinarily stout, short legs, while Anomalopteryx parva, perhaps the smallest Moa known, is said to have been about the size of a turkey. The validity of some genera and species is, however, questionable. Most writers think that the female was larger than the male. Mr. De Vis has described a fossil femur from Queensland as D. queenslandiae,^[33] but it may belong to the Dromaeidae. According to native testimony the habits were sluggish, but the birds were dangerous to approach; they lived in pairs and fed upon green shoots and roots of ferns, making a nest of a pile {43}of grass and leaves. We are told that the eggs found with the remains were dark green, light green, or yellowish, but the last colour at least probably refers to faded specimens.

VI. AEPYORNITHES.

Quite as remarkable as the Moas are the immense, massive-limbed forms of the Family Aepyornithidae, supposed by many to be identical with the "Ruc" or "Roc" of the Venetian traveller Marco Polo, and of the Arabian Nights. If this is the case, the size of the birds and their eggs must have been absurdly exaggerated, since the largest species known probably stood about seven feet high, and the egg is certainly not as big as a butt; nevertheless, the fact of the Roc being accredited to Madagascar makes it probable enough that the fables were engrafted upon Aepyornis, which was an inhabitant of that island. The eggs were first brought to the notice of ornithologists by Strickland in 1849, while soon afterwards Isidore Geoffroy St.-Hilaire obtained two of them, with some fragments of bones.^[34] These eggs, which exceed all others in magnitude, measuring some thirteen inches by nine and a half, have now been obtained in considerable numbers, with a large quantity of fossil remains of the birds themselves; and in consequence about twelve species have been indicated, and a second genus, Mullerornis.^[35] It is supposed that some of them were in existence not more than two hundred years ago. The most salient points of their structure are the long, stout legs, with four toes and broad flat metatarsi, the apparently rudimentary humeri, the absurdly short keel-less sternum, and the frontal pits, indicating a large crest, comparable to that supposed to have existed in certain of the Dinornithidae.^[36] The shell of the eggs, some of which contain two gallons, is used by the natives to hold liquor, and is slightly pitted.

* * * * *

It will be remembered that, in the arrangement here followed, Dr. Gadow placed the Stereornithes under the head of Neornithes Ratitae, though not under that of Ratitae in the restricted {44}sense; but it should be noted that their systematic position was not by any means assured, though justified by what was then known of these extraordinary fossils, of which the sternum has not even yet been brought to light. Remains of various forms, chiefly of gigantic size, have been disinterred from the Miocene strata of Santa Cruz in Patagonia, one of which (Phororhachos) was described in 1887 by Dr. Ameghino,^[37] from its mandible as an Edentate Mammal, though four years later^[38] he arrived at the more correct conclusion that the jaw was to be referred to a bird. In 1891, moreover, Señores Moreno and Mercerat^[39] proposed a new Order with the name of Stereornithes, when publishing a series of fine plates; while Dr. Ameghino, who criticised their work, reduced the nine genera created therein to the smaller number of three.^[40] Another paper by the author last named,^[41] and two by Mr. Lydekker^[42] should be consulted by those interested in the details of the subject, while an admirable summary will be found in Professor Newton's Dictionary of Birds. In a review of Dr. Ameghino's paper on these birds,^[43] Mr. C. W. Andrews stated that Phororhachos and others of the "Stereornithes" were not truly Ratite, but were Carinate forms in which the wings had undergone reduction, and suggested that possibly they were related to the parent stock of the Gruiformes, approximating particularly to Cariama (Dicholophus). Shortly afterwards Dr. Ameghino's collection was acquired by the British Museum, and a study of the specimens themselves has not caused the reviewer to change his opinion.^[44] Some members of the group (e.g. Mesembriornis) are perhaps truly Ratite, and one at least (Dryornis) belongs to the Cathartidae. Phororhachos is remarkable for the immense size and heavy build of the skull, to which the legs, huge though they sometimes are, bear no proportion; the maxilla is exceedingly compressed, yet very deep, and ends in a strong hook, while the long massive mandible curves upwards to meet it. There is a quite or nearly complete interorbital septum in this case, as opposed to Apteryx, and, to a considerable extent, to the Dinornithidae; {45}while the nostrils are pervious, and the quadrate articulates with the skull by two heads, contrary to what occurs in the Ratitae proper. The furcula is existent, but extremely slender; the metatarsus is more or less elongated, the hallux is present, the wings are small but well developed, and the tail is said to be long, with a considerable number of separate vertebrae.

This genus includes the species P. longissimus, P. inflatus, P. platygnathus, P. modicus, P. gracilis, and P. sehuensis; Brontornis, which has a shorter and wider mandible and smaller but stouter metatarsi, possesses in B. burmeisteri a form as large as Aepyornis maximus, while Opisthodactylus and other proposed genera are too imperfectly known to deserve consideration in our limited space.

Besides the above, Dr. Gadow classed with the Stereornithes, Diatryma of New Mexico, known from a metatarsus; Dasornis of the London Clay, described from fragments of a skull; Remiornis from the neighbourhood of Rheims, of which several imperfect bones have been found; and Gastornis of both England and France, of which a fair number of parts have been unearthed. All occur in the Eocene, but the question of their relationship is by no means settled, and some writers consider Gastornis to be nearly allied to the Anseres. This form appears to have been of the size of an Ostrich, with long leg-bones and short weak wings, and was probably flightless. Three species have been propounded, G. parisiensis, G. klaasseni, and G. edwardsi.

* * * * *

(B) With regard to the difficult question of the position in the system of the Neornithes Odontolcae, a few introductory words of explanation are necessary. In 1872 Professor Marsh bestowed upon two fossils from the Cretaceous deposits of Kansas the names of Hesperornis and Ichthyornis, which he proposed in the following year^[45] to comprise in a Sub-class Odontornithes, so called from the presence of teeth in the jaws. Subsequently^[46] he divided this Sub-class into two Orders, Odontolcae and Odontotormae, the former containing Hesperornis, with the teeth arranged in grooves, and the latter Ichthyornis, where they were placed in distinct sockets. His views have been controverted by many writers, but Mr. Lydekker–an authority of great weight in this connexion–while fully admitting the affinity of the first form to {46}the Divers, and the resemblance of the second to the Gull-tribe, proposed in 1891^[47] to retain the term Odontornithes for a series of birds ancestral to the modern series of toothless Carinatae, for which he adopted the title Euornithes, used in a narrower sense by Dr. Stejneger. It has, however, been decided to follow Dr. Gadow on this point; while the marks of distinction given below make it seem at least probable that, whereas Ichthyornis may be referred to the Carinate division, Hesperornis should be placed in closer proximity to the Ratite forms. Our Neornithes Odontolcae consequently contain the Hesperornithes, the Enaliornithes, and Baptornis, all of which appear to be nearly related.

Hesperornis regalis, which stood about three feet high, and H. crassipes, of even larger dimensions, had blunt teeth in the {47}grooves of both maxilla and mandible, the number being thirty or more below, but considerably less above, where they did not reach to the anterior extremity. The bill was long and pointed, the rami of the lower jaw being entirely separate; the head was rather small, the neck was long, and the quadrate bone articulated with the skull by one knob only. The sternum was long, broad, and flat, without keel; the furcula was decidedly reduced, the metatarsus was moderate and laterally compressed; there were four toes, all directed forwards and probably webbed; the wing was rudimentary, being little more than a humerus; the tail was fairly long and broad, but had no pygostyle. Enaliornis barretti and E. sedgwicki of the Cambridge Greensand had leg-bones very similar to the above, but being only known from fragmentary remains, their position is uncertain; while the same may be said of Baptornis of the North American Cretaceous strata, which, like the two last-named, is much smaller than Hesperornis.

NEORNITHES CARINATAE

BRIGADE I–LEGION I (COLYMBOMORPHÆ). ORDERS: ICHTHYORNITHES–COLYMBIFORMES–SPHENISCIFORMES–PROCELLARIIFORMES

(C) The Neornithes Carinatae, or birds which, with few exceptions, have a keel to the sternum, include all the remaining members of the Class. It is unnecessary to recapitulate the distinctions between these forms and the Ratitae, to be found on p. 26, but it may be well to reiterate that it is the sum of all the characters that constitutes the difference, and to point out that in one or more of the items several of the Carinatae agree with the members of the aforesaid group, though totally at variance with them in the aggregate. Claws on the manus are found on the pollex and index in certain of the Anseres, Cathartae, and Accipitres, and on the pollex alone in some Anseres, Accipitres, and Galli, with individual instances in other birds.

Order I. ICHTHYORNITHES.

Enough has already been said with regard to the position of the Order Ichthyornithes, with its sole Family Ichthyornithidae; but it remains to discuss the several members. Ichthyornis victor, I. dispar, and the other species were small forms of about the size of a Partridge, with the habits and appearance, it is presumed, of Terns or Gulls.^[48] The head was extremely large {49}in proportion to the remainder of the skeleton; the beak was long and pointed, with entirely separate rami to the mandible; the sharp teeth, fixed regularly in distinct sockets, were inclined backwards, and occupied the whole of the lower and at least the posterior half of the upper jaw; the keel of the sternum was large and broad; the dorsal and cervico-dorsal vertebrae were biconcave, as in Archaeopteryx, and perhaps to some extent in Enaliornis; the quadrate articulated to the skull by one knob, as in the Neornithes Ratitae and Neornithes Odontolcae; the metatarsus was short and the whole foot small; a furcula was probably present; the wings were well developed, indicating great powers of flight; while the tail was comparatively short, and ended in a pygostyle. It will be observed that of these characters the formation of the jaw and its teeth, the biconcave vertebrae, and the articulation of the quadrate, are those that chiefly distinguish the Order from the rest of the Carinatae. Apatornis celer, also from the Cretaceous deposits of Kansas, is probably to be placed here, but other genera described from the same strata cannot yet be certainly classified.^[49]

Order II. COLYMBIFORMES.

The Colymbiformes constitute a very archaic Order of Birds, and hold a somewhat isolated position. Older writers combined them with the Alcidae as a group Pygopodes, but recent anatomical investigations make it clear that Auks have more affinity to Gulls, which again trend to the Limicoline alliance. As regards structure, the two Sub-Orders Colymbi and Podicipedes, with their Families Colymbidae, or Divers, and Podicipedidae, or Grebes, may be here treated together. They are all water-birds with webbed or lobed toes and extraordinarily flattened metatarsi. The sternum in the Colymbidae is much longer than broad, in the Podicipedidae short and wide, while the furcula is Y-shaped; the neck is more or less elongated; the bill in the former Family is strong, straight, acute, and compressed, in the latter moderate and sometimes recurved, being either slender, as in Aechmophorus, or very stout, as in Podilymbus. The scutellated metatarsi are set very far back, and are fairly long, the procnemial process of the tibia being remarkably elongated, though Grebes alone have a distinct patella; the hallux is very small and has a small membrane, {50}but whereas Divers have the anterior toes fully webbed, their allies have them surrounded by large lobes of skin, connected only at the base. The claws are abnormally broad and flat in Grebes, the outer margin of the third being serrated. In the Colymbidae the wing is short, narrow, and pointed, with eleven primaries and about twenty secondaries; in the Podicipedidae it is still shorter and concave in form, with twelve primaries but rarely twenty secondaries; in the latter no true rectrices can be distinguished, though a tuft of downy feathers exists, while in the former they are normal though much reduced, and number from eighteen to twenty. Grebes have bare lores, and are frequently adorned in the breeding season with crests or tippets of a golden or brownish colour; the dense glossy plumage being more commonly used for decorative purposes than the duller coats of Divers. The tongue is always long and pointed, the syrinx is tracheo-bronchial, the nostrils are pervious, an aftershaft is present, and both adults and young are uniformly downy. Fossil remains from the Oligocene of France and southern England, indicating a genus intermediate between the two Families, have been named Colymboïdes.^[50]

Fam. I. Colymbidae.–Colymbus septentrionalis, the Red-throated Diver of the Arctic and sub-Arctic parts of both worlds, is brownish black in summer, with white under-parts and white specks above; the head and neck are lead-coloured, except the nape, which is black with white streaks, and the mid-throat, which is reddish-chestnut. C. arcticus, the Black-throated Diver, found in the same regions though with a different distribution, as for instance in Scotland, is blacker, with white bars as well as spots; the crown and hind neck being ashy grey, the sides of the latter striped with black and white, and the throat purplish-black, interrupted by a semi-collar of white with vertical black lines. C. pacificus of western North America is barely separable. C. glacialis, the Great Northern Diver, has a much more restricted range, breeding in Iceland, Greenland, and the Fur Countries as far west as the Great Slave Lake, where it meets C. adamsi (hardly differing except in the yellowish-white bill), which extends thence to Northern Asia, and possibly to Spitsbergen and Jan Mayen. The former is black above, with belts of white spots making a "chess-board" pattern; the lower surface is {51}white, and the throat is crossed by two bands of white with longitudinal black bars, while the head and neck are black with a purplish gloss, changing to green below. In winter most Divers are found down to the northern tropic, at which season the throat becomes white, as it is in the young, in which the feathers of the upper parts are duller with whitish edges. The sexes are similar; the bill is normally black, and the feet are bluish or greenish grey. The downy chicks are sooty above.

Divers are not usually gregarious, and unless driven by stormy weather to inland waters, are essentially marine, except during the breeding season, when they ascend the rivers and seek their customary nesting-sites on the moors, the Black-throated species showing a somewhat greater preference than the rest for islands in the lakes they frequent, but the Red-throated often selecting small pools, or even "flows," among the heather. The two eggs, greenish- or reddish-brown in hue, with blackish and grey blotches and spots, are laid on a mere depression in the grass or sand close to the water's edge, or upon a mass of green vegetation which is occasionally semi-natant. Incubation is said to last four weeks. As a rule the female performs this duty, lying flat upon her eggs, and gliding or scrambling off when disturbed, whence a distinct track is often visible upon the turf. On leaving the land a dive is taken {52}to a considerable distance, then both parents swim towards the intruder with the body partly submerged, and finally, if thoroughly scared, they rise heavily on the wing to circle round with outstretched neck before betaking themselves with rapid but laboured flight to some neighbouring lake, from which they return at intervals until the coast is clear. They descend from aloft noisily and with great impetus, the splashing plunge being followed by a gliding movement, leaving a broad furrow behind, while on land they move with difficulty, and rest on the metatarsus. Their croak, or loud, clear, melancholy cry is often heard before storms, whence the Red-throated Diver is called Rain-goose in Scotland; the food consists chiefly of fish, brought to the surface and swallowed with a jerk, but crustaceans, molluscs, and perhaps aquatic insects vary the diet. The young take to the water readily, but the female occasionally carries them on her back.

Both Divers and Grebes swim strongly, the flat of the metatarsus meeting the water during the back stroke, and the thin edge on the return. When submerged they do not use the pinions.

Fam. II. In the Podicipedidae both sexes are mainly dusky brown or blackish grey above, and silvery white below, often with some white on the wing; so it will only be necessary to note hereafter the distinctive ornaments or bright colours which are invariably lost in winter. Podicipes fluviatilis, the Little Grebe or Dabchick, ranging over Europe, Africa, and Asia to the Malay Countries and North Australia, has rich chestnut cheeks, throat, and sides of the neck, horn-coloured bill, and greenish feet. In winter the chestnut fades to buff with a white chin. Count Salvadori^[51] considers P. gularis of Australia and Papuasia and {53}P. tricolor of the Moluccas separable, P. pelzelni of Madagascar being hardly so. P. dominicus, extending from the southern United States to Patagonia, differs in its black throat. The Little Grebe breeds commonly in Britain, while P. cristatus, the Great Crested Grebe or Loon, only nests on our largest waters, covering, however, a wide range in Europe, Africa, Asia, Australia, and New Zealand. It has a bifurcate crest of brown, a chestnut ruff tipped with black round the cheeks and throat, a red base to the bill and greenish feet. P. griseigena, the Red-necked Grebe, which wanders to our shores, but breeds in the north of the Palaearctic and Nearctic Regions, and perhaps occasionally in Morocco, has the foreneck chestnut, a line above the cheeks white, and the base of the bill yellow. Some writers denominate the North American and East Asiatic form, P. holboelli. P. auritus, the Slavonian Grebe of the sub-Arctic portions of both worlds, has a tuft of golden chestnut feathers on each side of the head, an ample black ruff, rufous chest and flanks, black bill and greenish feet; P. nigricollis, the Eared Grebe, of Central and Southern Europe, Africa, temperate Asia, and western North America, has merely golden ear-tufts, with a black chest. Both visit us at certain seasons. Finally, P. nestor inhabits South Australia; P. rufipectus New Zealand; P. caliparaeus, P. rollandi, and Aechmophorus major America south of Peru and Brazil; Ae. occidentalis western North America; Podilymbus podiceps nearly all the New World: and Centropelma micropterum Lake Titicaca only. The first two have white hair-like filaments on the head, the third and fourth elongated ear-coverts of golden brown or black and white; while Podilymbus is remarkable for its stout whitish bill with median black band and its black throat, Centropelma for its aborted wings and flightless condition. Podicipes taczanowskii, of Lake Junin in Peru, differs from P. caliparaeus in its longer and lighter bill and feet, and grey-brown ear-coverts. Grebes in the down are streaked with white or buff on a dusky ground, while some have a naked red space on the crown.

These migratory birds frequent reedy streams and stagnant waters in summer, being companionable, though not gregarious; hard weather, however, drives them to the sea. They walk fairly well, though awkwardly, and sit upon the whole metatarsus; but the chicks progress on "all fours," using the wings almost {54}as forefeet.^[52] They fly straight and rapidly, with head and feet extended, but have difficulty in leaving the water; they dive at the slightest alarm, their quick sight enabling them to vanish below the surface at the flash of a gun, to reappear, with hardly a ripple, at a distance. Frequently it requires much patience to obtain a second view, as their bodies can be submerged to any extent, and at times the bill alone is exposed. In swimming they jerk the head and often rise vertically to shake their wings. They descend from the air with a splash and a glide, while in diving the feet alone act as oars, the young soon equalling their parents in this respect. The note is a harsh croak in the larger forms, a softer sound or whit-whit in the smaller; the food consists of fish when procurable, but small reptiles, amphibians, molluscs, crustaceans, insects, and vegetable matter are frequently added, and feathers of some size are constantly found in the stomach. The nest, a pile of aquatic weeds or rushes of varying bulk, is fixed among reeds, sedges, semi-natant masses of herbage, or, more rarely, upon low branches of trees or bushes verging upon the water. Should this rise higher, fresh materials are added. From three to six bluish-white eggs with a smooth chalky covering are laid in a slight depression above, but being covered with wet weeds by the female on leaving, soon become stained with brown. The bill is used in concealing them, nor does an invader's presence usually hinder the operation. Incubation lasts from twenty-one to twenty-four days. Both sexes are said to assist, and the mother carries the nestlings on her back, or even dives with them in that position.

Order III. SPHENISCIFORMES.

The Order Sphenisciformes, with its Sub-Order Sphenisci, contains only those remarkable marine birds the Penguins (Fam. Spheniscidae), the life of which is chiefly spent on the stormy waters of the Antarctic seas. Coupled by former writers with the Auks, their northern analogues, it has now been shown that the slight external similarity of the two groups is utterly misleading, the nearest allies of the primitive forms here treated being the Petrels on the one hand and the Divers and Grebes on the other. Their unique structure is correlated with very peculiar habits.

The horny sheath of the maxilla is composed of from three to five more or less distinct pieces, while the powerful bill may be long, thin, and slightly decurved, as in Aptenodytes and Pygosceles; shorter and pretty broad, as in Eudyptes; or very stout, short, and compressed, as in Spheniscus, where the prominent hook of the culmen overhangs a truncated mandible. The three metatarsals are not completely fused as in other birds (p. 10), the scutellated metatarsus itself being shorter and broader than in any other Family, except the Fregatidae; the legs are set far back, the tibia is hardly visible, and the short thick toes are directed forwards, the small hallux alone having no web. Even more striking are the wings, which are totally devoid of normally-developed quills, though the number of feathers is very large, the primaries themselves amounting to about thirty-six; these flippers or paddles have highly compressed bones with no power of flexure, but work freely from the shoulder in rotatory fashion, requiring a corresponding increase of strength in the muscles of the neighbouring parts. The numerous rectrices are fairly long and stiff in Aptenodytes, Pygosceles, and Eudyptes, but shorter in Spheniscus, having considerably reduced vanes. On the body we find no naked tracts, but a uniform covering of small scale-like feathers, with or without barbs, and an equally uniform distribution of down both in adults and young; the moult, moreover, is accomplished in an exceptional manner, the plumage being shed in masses, and that of the wing gradually flaking off above the new coat. The process apparently occupies about ten days.^[53] Long superciliary crests occur in Eudyptes, the mandible is more or less feathered in Aptenodytes and Pygosceles, and the metatarsi are clothed besides in A. forsteri. The furcula is U-shaped, the syrinx tracheo-bronchial, the tongue rudimentary, an after-shaft is present, and the plentiful subcutaneous fat produces a marketable oil.

Penguins^[54] have been said to derive their name from the Latin pinguis (fat) or the English "pin-wing," i.e. pinioned wing, but such nautical appellations are usually obscure. The French term them "Manchots." These birds rest on the whole metatarsus, the bill usually pointing upwards; their gait on land is ludicrous, but often fast, a vertical position being generally preserved, while they endeavour to waddle along on their toes with constant flapping of the pinions, every now and then partially losing their balance {56}and regaining it by the aid of their flippers. Several species are called Rock-hoppers, from their manner of hopping upon the boulders. They are, however, rarely seen on land, except in the breeding season, though equally gregarious at all times, swimming in "schools" and resorting in vast numbers to their "rookeries." When submerged, the wings act as paddles with alternating rotatory action, and the feet as rudders; but on the return to the surface the latter naturally become the propellers. The note is a croak, a scream, a murmuring sound, or, in the young, a whistle. The food of crustaceans, cephalopods, and other molluscs, is varied by fish or a little vegetable matter, and accompanied by a mass of pebbles, often ejected near the breeding places. The nest of grass and leaves–more rarely of twigs, pebbles, clay or rubbish, when herbage is scarce–may be in burrows, among tussocks, under stones, in caves, or in the open; the two coarse-flavoured eggs being white or greenish-white, with a variable amount of chalky incrustation. The male is said to assist in incubation, which lasts about six weeks; the parents sit very closely and feed the blind young for an exceptionally long period, by inserting their bill in that of the nestling. Pugnacious and thievish towards one another, Penguins are usually fearless on land, though, when they are irritated, the beak can inflict a very severe bite.

The range extends southwards from the Galápagos round Cape Horn to the Falkland Islands, a few stragglers reaching Brazil; thence breeding stations are found eastwards in Tristan da Cunha, off the Cape of Good Hope, in the Crozets, Marion, and Amsterdam Islands, Kerguelen Land, and so on to the south of Australia and New Zealand, with the Antarctic regions as far as man has penetrated. The largest form is Aptenodytes forsteri, and the smallest Spheniscus minor, about 36 and 19 inches long respectively; the sexes are alike in colour, or the female may be a little duller and resemble the young. The bill and feet are usually reddish-brown, black or grey, but the latter may be whitish. The nestling in down is blackish- or yellowish-brown with white lower parts.

A. forsteri, the Emperor Penguin of Victoria Land and the adjacent seas, is blackish-grey, with white breast and belly and an oval yellow spot on each side of the head. It is particularly tame, and moves at a marvellous rate by lying on the snow and propelling itself with its feet.^[55] A. pennanti, the King Penguin of {57}Kerguelen Land, the Falklands, Crozets, Auckland, Macquarie, Campbell, and other southern islands, apparently confounded with the last-named under the title of A. patagonica, is distinguishable by the longer bill, more orange chest, and lack of feathers on the sides of the mandible and metatarsus. The crowded breeding grounds are flat spaces of hard soil covered with slime, and are often quite apart from the general quarters. When disturbed the birds utter a loud "urr-urr-urr," and run to the sea at a great pace, maintaining an upright position; while they pass to and from the water singly, and not in flocks, as do other species.^[56] The pyriform eggs are sometimes held up by the parents' feet. Pygosceles taeniata, the "Gentoo," of similar but more restricted range, is bluish-black above and on the throat, having the lower parts, the margins of the flippers, and a band across the crown white. Dense colonies are found both near the sea and several miles inland, a regular path being often beaten down by the birds traversing it in company; the nests consist of a little herbage in a hollow, or are small conical mounds of stones and clay, lined with feathers and down, the oval eggs being frequently of unequal size. The note is an unmelodious bark.^[57] P. adeliae inhabits the icy regions of the far south.