96 Aves — Classification. 



In Africa we have the living Ostrich which once extended 

 through Arabia and Persia, into India, where its fossil remains 

 have been found in the Siwalik Hills. In Madagascar have been 

 found the remains of the extinct JEpyomis. In New Guinea we 

 have the living Cassowary, which also extends into Australia, 

 where the Emeu occurs both living and fossil, and the 

 Dromomis, a fossil bird as large as the Dinomis. In New 

 Zealand we have the genera Dinomis, Anomalopteryx, Emeus, 

 Pachyornis, all extinct ; and the living Apteryx. It may be 

 remarked that these numeroas and widely distributed flightless 

 birds are probably derived from flying ancestors, and may have 

 arisea separately in different parts of the world. 



Although it is clear that birds are the descendants of some 

 group of reptiles, it is by no means certain which. Professor 

 Huxley's suggestion that the Dinosaurs are the ancestors of 

 birds, has been widely adopted, but probably the resemblances 

 between them are mainly due to the similar bipedal mode of 

 progression of the birds and of the Dinosauria to which they 

 have been compared. 



Birds considered as a Glass. — Although the remains of Birds 

 are extremely rare in a fossil state, they furnish the following 

 suggestions for a scheme of classification* : — 



Sub-class I. — Saurum (Lizard-tailed Birds) .f 



The metacarpal bones not anchylosed together ; the tail 

 longer than the body ; jaws furnished with teeth ; three 

 free digits in the nianus, all armed with claws ; vertebra? 

 biconcave. Ex. Archcvopteryx. 



Sub-class II. — Ratitj; (Raft-breasted birds). f 



Division A, Birds with teeth. 



[a, with biconcave vertebras, at present unknown.] 

 h, with saddle-shaped vertebras. Ex. Hesperornis. 



Division B, Birds without teeth. 



All the later Tertiary and existing forms of raft- 

 breasted birds. 



Sub-class III. — Carixatj: (Birds with a keeled sternum). 



Division A, Birds with teeth. 



a, with biconcave vertebras. Ex. Ichthyornis. 



[b, with saddle-shaped vertebrae, at present unknown.] 

 Division B, Birds without teeth. 



All the later Tertiary and existing forms of Carinate 

 Birds. 



* A. Newton: "Encyelop. Brifc.," 9th edit., vol. xviii., pp. 2-50, 1885. 

 t For explanations of these terms see Index Collection in entrance hall. 



