Crocodiles and Alligators 



551 



clusively fish-eating propensities. 

 Full-grown examples of the gavial 

 may attain to a length of 20 feet. 



The TYPICAL or MISSISSIPPI 

 ALLIGATOR is, as its name denotes, 

 a North American form, having 

 the modified dental and other 

 structural details previously referred 

 to, but otherwise in size and its 

 aggressively destructive habits 

 nearly corresponding with the 

 Oriental crocodile. A second 

 species of alligator is found in 

 China. 



In the tropical South American 

 rivers the place of the alligator 

 is occupied by the CAIMANS, some 

 of which attain to huge pro- 

 portions, and are distinguished 

 from the former by the greater 

 development of the bony armature 

 of both their back and under- 

 surface, and by certain essential, 

 but to the lay reader obscure, 

 modifications of the skull. An 

 example of the (TREAT CAIMAN once 

 did duty as a riding-horse to the 

 naturalist Waterton, as all those 

 familiar with his book of travels 

 will remember. 



The habits of the 



caiman 



Photo by Scholastic Photo. Co.] [Parson's Green. 



MISSISSIPPI AND CHINESE ALLIGATORS. 

 The Chinese species, which is the smaller of the two, feeds mainly upon fish. 



differ somewhat locally. From the main stream of the Lower Amazon they are in the habit 

 of migrating in the dry season to the inland pools and flooded forests. In the middle districts 

 of the same river, where the drought is excessive and protracted, the caimans are addicted to 

 burying themselves in the mud till the rains return; while in the upper reaches of the 

 Amazon, where the droughts are not prolonged, the caimans are perennially present. The 

 eggs of these reptiles are much esteemed for food by the natives of Dutch Guiana. 



CHAPTER, II. 



TORTOISES AND TURTLES. 



r I 1HE order of the Chelonians, including the Tortoises, Turtles, and Terrapins, with their 

 JL allies, constitutes one of the most distinct and readily defined groups of the Eeptile 

 Class. The more or less complete bony shell, or carapace, which encases the body, and 

 into which both head and limbs can in many cases be completely retracted, separates these 

 reptiles very widely from the other orders. In some respects certain details of the skull- 

 structure assimilate them to the Crocodiles; but here again there is an entire absence of the 

 rows of formidable teeth, the upper and lower jaws being sharply pointed, covered with horn, 

 and thus converted into a trenchant beak. The two leading groups of the Tortoises and the 

 Turtles are distinctly separated, by the respective conformation of their limbs, for a terrestrial 

 or aquatic existence. The Tortoises have normal walking-legs, with toes and, in most instances, 

 claws, fitting them for walking on the land or burrowing into the earth. In the True Turtles 



