244 



VERTEBRATE ZOOLOGY 



The geographic distribution of the crocodiles is wide, but con- 

 fined chiefly to the tropical regions. Thej' are found over a large 



part of Africa, in India, Southern 

 China, Malaysia, South and Cen- 

 tral America, and along the Gulf 

 of Mexico in North America. 

 Formerly they occurred in Europe 

 and Northern Asia. 



Habits. — The crocodiles, alli- 

 gators and gavials are all fierce 

 predaceous creatures, most of 

 them being enemies of both man 

 and beast wherever they grow. 

 The older they become the more 

 wily and dangerous they live 

 and the more apt to become 

 man-liunters. Their rusty, bark- 

 \^ j^ ""'"' Uke backs give them the ap- 



^^ ' T.'fl/i- — V pearance of partly sunken logs 



and many an unwary creature 

 attempting to gain support upon 

 such a "log" has suffered a rude 

 awakening. The eggs are laid in 

 the sand much after the fashion 



^ ^ Kl of turtles. They reach a great 



age, probably often breaking over 

 the century mark. 



Living Crocodilia belong to two 

 families: Ga\'ialidoe and Croco- 

 dilida\ 



Family Gavialidae. — There is 

 but one living species of gavials, 

 Gavialis gangdicus (Fig. 137, C), 

 confined to the Ganges and other 

 large rivers of India. They reach 

 a length of over twenty feet, but 

 are loss dangerous to man than are the truc^ crocodiles, although they 

 are believ(>(l to be ever on the alert to capture man. As a matter of 

 fact it is stated by competent authorities that they never attack man, 



Fig. 136. — Brain of Alligator, from 

 above. B. ol, olfactory bulb; G'. p, 

 epiphysis; H. H, cerebellum; ^[e(!, 

 spinal cord; i\/. H, optic lobes; N. 11, 

 medulla oblongata; 1'. H, cerebral 

 hemispheres; I -XI, cerebral or 

 cranial nerves; 1, 2, first and second 

 spinal nerves. (From Wiedersheim.) 



