HEPTILES. 287 



absorbed and finally thrown off. It was supposed by one 

 writer that the Crocodile had so many teeth as there are 

 days in the year. Professor Owen* remarks that the number 

 of teeth developed by a Crocodile, throughout its entire life, 

 would doubtless exceed even this liberal allowance. But with 

 regard to those which are in use at any given time, the 

 number is now well ascertained: the Crocodile of the Nile 

 has sixty-eight; the common Alligator (A. Indus], seventy- 

 six; and the great Gavial (Gavialus Gangeticus), one hundred 

 and eighteen. 



This notice of saurian reptiles, howevers light, cannot be 

 closed without some reference to the strange forms and gigantic 

 proportions of the fossil species discovered in these countries. 



Fig. 230. ICTHYOSAURUS. 



One of them, the Icthyosaurus (Fig. 230), or Fish-lizard, 

 received that name from some resemblance of the vertebrae to 

 those of fishes. Seven or eight species are now known, 

 exhibiting singular combinations of structure, such as are no 

 longer found united in any living animal. Some of these 

 individuals were not less than thirty feet in length. They 

 were marine reptiles, preying upon fishes whose scales and 

 bones, found in hardened masses in the interior of the skeletons r 

 and strewed elsewhere in great abundance, unfold a tale 

 respecting the former inhabitants of the ancient ocean from 

 which these islands were upheaved. 



Fig. 231. PLESIOSAURUS. 



Another genus is that of the Plesiosaums^ (Fig. 231). 

 " To the head of a Lizard is united the teeth of a Crocodile; 



* Odontography, p. 286. 



f From two Greek words, meaning "near to" and "a Lizard." 



