7i6 



PHYLUM CHORDATA : CLASS REPTILIA 



male, the oviducts from the ovaries in the female, open into the cloaca, 

 which has a longitudinal opening. The penis is on the anterior surface 

 of the cloaca. 



The eggs, which in size are like those of geese, have a thin calcareous 

 shell, are buried in excavated hollows, and, warmed by the sun, hatch 

 without incubation. 



Of one species of crocodile it is known that the mother opens up the 

 nest when the young, ready to be hatched, are heard to cry from 

 within the eggs. The mothers take some care of the young, which 

 require to be defended even from the appetite of the males. 



Crocodiles are relatively sluggish, and fond of basking passively, 

 sometimes hiding in the mud during the hot season. They are remark- 

 able for the long continuance of growth, which does not seem to have 

 so definite a limit as in most other animals. 



Classification of Crocodilia 



(a) The true Crocodiles, of the genus Crocodilus, occur in Africa. 

 Southern Asia, tropical Austraha, Central America, and the West 

 Indies. 



The Indian crocodile (C. porosus) may measure about i8 ft. in 

 length, and even larger forms have been recorded. The sacred African 

 crocodile (C. vulgaris) is still formidably common in some of the 

 fresh waters of tropical Africa. 



The eggs and the young are often eaten by a mammal called the 

 Ichneumon, and by a species of lizard. The adults have few enemies 

 except man. They seem to live in friendly partnership with little 

 birds (Pluvianus cBgypticus), which remove parasites from the body, and 

 in their familiarity almost justify the account which Herodotus gives 

 of their cleaning the reptile's teeth. 



DIFFERENXES BETWEEN CROCODILES, ALLIGATORS. 



AND GAVIALS 



