EXISTING GROUP. 15 



the entire body of the victim ; and their teeth being adapted for seizing and 

 holding fast only, and not for biting, they are obliged to mangle the carcase, 

 tearing off single pieces by sudden strong jerks." This rending process is mainly 

 accomplished by lateral movements of the head and front portion of the body. 

 Too often, human beings, who incautiously bathe in crocodile-haunted waters, fall 

 victims to these bloodthirsty reptiles ; while there are instances of people being- 

 seized when merely stooping down to dip water from the river's marge. When 

 seized, the only way for an unarmed man to escape is, it is said, to thrust his 

 ringers into the creature's eyes and endeavour to gouge them out. To a consider- 

 able extent crocodiles are nocturnal in their habits, and during protracted droughts 

 many of them at least are accustomed to bury themselves in the mud, where they 

 become torpid. 



As regards their reproduction, crocodiles lay from twenty to sixty eggs, of 

 the approximate size of those of a goose, and invested with a hard, white shell. 

 These are deposited in some hollow in the sand of the bank, where, after being 

 covered to a greater or less depth, they are left to hatch. Whether the parent 

 always assists in the incubation does not appear certain, although this has been 

 proved to be the case in Madagascar by Dr. Voeltzkow. In that island the egg- 

 laying season lasts from the end of August to the end of September ; the usual 

 number of eggs in a nest varying from twenty to thirty. The nest is excavated 

 to a depth of about two feet in the dry white sand ; its lateral walls being under- 

 mined so as to allow the eggs to roll into the cavities thus formed from the 

 slightly elevated centre. Upon the summit of the completed nest, which is not 

 noticeable externally, the parent sleeps ; and when the young crocodiles are ready 

 for hatching they utter distinct notes, which are heard by the mother even 

 through a layer of two feet of sand. Digging down to the eggs, the parent 

 crocodile lays them open to the air, upon which the young reptiles make their 

 way out by perforating the shell at one extremity by the aid of a tooth specially 

 developed for this purpose, the whole process occupying as much as a couple of 

 hours. When hatched, the young crocodiles are led to the water by their parent, 

 whose attention they attract by uttering cries, which are, however, of a lower 

 pitch than those emitted while still in the egg. 



Existing Crocodiles. 



Family Crocodilid^E. 



The whole of the existing members of the order are included 

 aimans. .^ ^ gj^fe f am jly j which may be subdivided into half a dozen generic 

 groups. Of these, in some respects the most specialised are the caimans and 

 alligators, which, although closely allied, are now generally regarded as belonging 

 to distinct genera. Both caimans and alligators are characterised by their rela- 

 tively short and broad snouts, in which the .dges of the jaws are festooned, and 

 the nasal bones extend forwards to the aperture of the nostrils, 1 while the two 



1 This is shown in the figure on p. 2, where the nasals are the paired bones on the upper aspect of the skull, of 

 which the narrow points just project into the cavity of the nostrils. 



