The first order of Birds is that of the Cursores, or Runners, comprising the Ostriches, Rheas, Cassowaries, Emeus, and the singular Apteryx of New Zealand. The Cursores are characterised by the rudimentary condition of the wings, which are so short as to be useless for flight, and by the compensating length and strength of the legs. In accordance with this condition of the limbs, many of the bones retain their marrow, and the sternum (fig. 329, A) is destitute of the p?vminent ridge or keel, to which the great pectoral muscles are attached (hence the name of Ratitae, applied by Huxley to the order). In the Ostrich, the pubic bones of the pelvis unite to form a symphysis pubis, as they do in no other bird; and in all, the pelvic arch possesses unusual strength and stability. The legs are extremely robust and powerful, and the hind-toe is entirely wanting, except in the Apteryx, in which it is rudimentary. The anterior toes are two or three in number, and are provided with strong blunt claws or nails. The plumage presents the remarkable peculiarity that the barbs of the feathers, instead of being connected to one another by hooked barbules, as is usually the case, are remote and disconnected from one another, presenting some resemblance to hairs.
The order Cursores may be divided into the two sections of the Struthionidae and the Apterygidae - the former characterised by the absence of the hallux, and comprising the Ostrich, Rhea, Emeu, and Cassowary, with several extinct forms; the latter comprising only the Apteryx of New Zealand, and characterised by the possession of a rudimentary hallux.
The African Ostrich (Struthio camelus) occurs in the desert plains of Africa and Arabia, and is the largest of all living birds, attaining a height from six to eight feet. The South African Ostrich is often considered as a distinct species, under the name of S. australis. The head and neck are nearly naked, and the quill feathers of the wings and tail have their barbs wholly disconnected, constituting the ostrich-plumes of commerce. The legs are extremely strong, and are terminated by two toes only, these consisting respectively of four and five phalanges, showing that it is the hallux and the innermost toe which are wanting. The internal one of the two toes is much the larger, and is clawed; the outer toe is small and clawless. The pubic bones (fig. 329, B) are united in a ventral symphysis, and the wing is furnished with a long humerus. The Ostriches run with extraordinary speed, and can outstrip the fastest horse. They are polygamous, each male consorting with several females, and they generally keep together in larger or smaller flocks. The eggs are of great size, averaging three pounds each in weight; and the hens lay their eggs in the same nest, this being nothing more than a hole scratched in the sand. The eggs appear to be hatched mainly by the exertions of both parents, relieving each other in the task of incubation, but also partly by the heat of the sun.*
The American Ostriches or Rheas are much smaller than the African Ostrich, and have the head feathered, whilst the feet (fig. 329, E) are furnished with three toes each. The wings are rudimentary, and the phalanges are plumed and terminated by a spur. They inhabit the great plains of South America, and are polygamous. Three species are known, extending from Patagonia to Peru, but each inhabiting its own specific area.
The Emeu (Dromaius Novce-Hollandiae) is exclusively found in the Australian continent, and nearly equals the African Ostrich in size, attaining a height of from five to seven feet. The feet are furnished with three toes each, and the head is feathered. The throat, however, is naked, and the general plumage resembles long hairs, the feathers hanging down on both sides of the body from a central line or parting which runs down the middle of the back. The Emeus are monogamous, and the eggs are dark green in colour. The male Emeu is smaller than the female, and undertakes all the duties of incubation. Two varieties, or species, of the Emeu are known - one on the eastern and the other on the western side of Australia.
* Mr Sclater, however, states that the duty of incubation is entirely taken by the males.
Fig. 329. - Morphology of Cursores. A, Sternum of the Ostrich (Struthio camelus) : a-Scapula ; c Coracoid. B, Side view of the pelvis of the Ostrich : i Ilium ; p Pubis; is Ischium ; f Femur. C, Foot of Apteryx australis. D, Tarso-metatarsus of the Apteryx, showing the hallux placed high up on its posterior surface. E, Foot of the Rhea americana. *
The last living group of the Struthionidae is that of the Cassowaries, best represented by the Galeated Cassowary (Casu-arius galeatus), which inhabits the Moluccan Islands and New Guinea, and was first brought alive to Europe by the Dutch. It stands about five feet in height, and possesses a singular horny crest upon its head. The head and neck are naked, with pendent wattles, the wing has a short humerus, and the feet have three toes each. The general plumage is black, and the feathers more or less closely resemble hairs. The wings are rudimentary, each with five naked pointed quills. The male is much the smaller, and sits upon the eggs. Besides the Galeated Cassowary, other species have been described from the Malayan Archipelago and North Australia, at least nine species being now known to exist in all.
The second section of the Cursorial birds is that of the Ap-terygidae, comprising only the singular "Kiwis" (Apteryx) of New Zealand. The beak in the Apteryx is long, slender, and slightly curved, the tip being obtuse, and the nostrils placed at the extremity of the upper mandible. The legs are comparatively short, and there is a rudimentary hind-toe or hallux, forming a kind of spur, furnished with a claw (fig. 329, C and D). The wings are entirely rudimentary, and are quite concealed by the feathers, each terminating in a sharp claw. The feathers are long and narrow, and the tail is short and inconspicuous. The species of Apteryx are wholly confined to New Zealand, and are nocturnal in their habits, living upon insects and worms. Four species have been described, of which A. australis (fig. 330) is the best known.
As regards the distribution of the Cursores in time, it seems probable that some of the footprints of the Connecticut Trias (if ornithic at all) have been produced by birds belonging to this group. Leaving these doubtful instances out of sight, the Eocene Tertiary has yielded the first certain traces of Cursorial birds (the Dasornis of the London Clay). The most interesting remains of Cursores have, however, been found in the Post-Tertiary deposits of the southern hemisphere, and more especially in New Zealand. In this island have been found the remains of a number of large wingless birds, which form the family of the Dinornithidae, of which Dinornis (fig. 331) itself is the most important genus. All the members of this group (Dinornis, Palapteryx, etc.) are large Cursorial birds, the wings being useless for flight, and furnished with a rudimentary humerus. The hallux is wanting (Dinornis) or present (Palapteryx). The largest species is the Dinornis giganteus, one of the most gigantic of living or fossil birds, the tibia measuring a yard in length, and the total height being at least ten feet. Another species, the Dinornis elephantopus (fig. 331), though not standing more than about six feet in height, was of an even more ponderous construction - "the framework of the skeleton being the most massive of any in the whole class of Birds," whilst "the toe-bones almost rival those of the Elephant" (Owen). The feet in Dinornis were furnished with three toes, and are of interest as presenting us with an undoubted bird big enough to produce the largest of the footprints of the Triassic Sandstones of Connecticut. New Zealand has now been so far explored, that it seems questionable if it can retain in its recesses any living example of Dinornis; but it is certain that species of this genus were alive during the human period, and survived up to quite a recent date. Not only are the bones very numerous in certain localities, but they are found in the most recent and superficial deposits, and they still contain a considerable proportion of animal matter; whilst in some instances bones have been found with the feathers attached, or with the horny skin of the legs still adhering to them. Charred bones have been found in connection with native "ovens;" and the traditions of the Maories contain circumstantial accounts of gigantic wingless Birds, the "Moas," which were hunted both for their flesh and their plumage.
Fig. 330. - Apteryx australis. (Gould.)
Fig. 331. - Skeleton of Dinornis elephantopus, greatly reduced. Post-Pliocene.
New Zealand. (After Owen.)
In Madagascar, bones have been discovered of a bird as large as, or larger than, the Dinornis giganteus, which has been described under the name of the AEpiornis maximus. With the bones have been found eggs measuring from thirteen to fourteen inches in diameter, and computed to be as big as three ostrich-eggs, or one hundred and forty-eight hen's eggs. Though generally referred to the Cursores, AEpiornis has been sometimes regarded as a gigantic member of the Raptores.
Lastly, the Post-tertiary deposits of Australia have yielded the remains of an extinct Struthious bird allied to the Emeu, which has been described under the name of Dromaeornis.