VERTEBRATA. 229 



Opisthocomidce. Tinamidce. Ehynchotus. 



Opisthocomus. Nothura. Tinamotis. 



Tinamus = Crypturus 

 (Tinaraou). 



Chionidce. 

 Chionis. 



Order VII. STRUTHIONES. 



RATIT.E. BREVIPENNES. PLATYSTERN.E. PROCERI. 



Bill various. Breast-bone without the mesial keel. Wings 

 rudimentary. Barbs of the feathers not connected to one an- 

 other. 



All other birds have a keeled breast-bone ; and in no others 

 are the feathers so hair-like ; they have no accessory plumes in 

 the ostrich and Apteryx, while in the cassowary there are two. 

 The quill-feathers of the wings and tail are the ostrich-feathers of 

 commerce. Few air-cells are found in the bones. There is no 

 lower larynx. The feet are large ; the toes are two or three, there 

 being no back toe, except a rudimentary one in Apteryx. In the 

 ostrich alone are the two pubic bones united, and it has no, or only 

 rudimentary, clavicles. In the foetal state of this bird there are 

 18 caudal vertebrae, in the adult they are reduced to 9. In the 

 emu, in both sexes, there is a large membranous sac opening into 

 the trachea ; its use is unknown. Apteryx has its nostrils placed 

 at the tip of the bill. 



The intestinal canal is very complicated in the ostrich ; the 

 caeca are upwards of two feet in length, but they are absent in the 

 cassowaries. The stomach or gizzard is very muscular. 



Ostriches are polygamous ; both parents attend to their eggs, 

 which are laid in holes in the sand. The nandou ( E hea ameri- 

 cana) is also polygamous, takes the water readily, and is a good 

 swimmer. Emus and cassowaries are monogamous. Apteryx 

 is nocturnal. Dinornis and Mpyornis, both extinct, are amongst 

 the largest of known birds. The egg of JEpyornis maximus was 

 equal to about 148 hen's eggs, while the egg of the apteryx is one 

 quarter the weight of the bird. 



The following short list includes all the well-ascertained living 

 forms of what probably has been a very extensive group : The 

 ostrich (Struthio camelus), three nandous (Ehea americana, E. 

 darwinii, and It. macrorhynchd), two emus (Dromceus nova- 

 hottandicB and D. irroratus), five cassowaries (Casuarius galeatus, 



