ALLIGATORS, GAVIALS, FOSSIL CROCODILES. 555 



are less aquatic in their habits than the Crocodiles. They are 

 distinguished by the shortness and roundness of the muzzle ; by 

 the reception of the longest teeth of the lower jaw into cavities 

 in the upper ; by the absence of the ridge of scales on the hind- 

 legs ; and by the much inferior development of the webs between 

 the toes. They frequent swamps and marshes, rather than rivers ; 

 and are occasionally seen basking on dry ground, during the day, 

 luxuriating in the heat of the sun. It is during the night that 

 they are most active ; and they then set up a loud bellowing, not 

 unlike that of a bull. Several species of Alligator are known ; 

 vary ing in length from twoto morethan twentyfeet. The Gavial, 

 or Crocodile of the Ganges, of which only one species is known, 

 is the largest of the living Saurian Reptiles ; and differs remark- 

 ably from the preceding, in several particulars. The muzzle is 

 extremely prolonged and narrow, forming a sort of beak ; and 

 this is swollen at its extremity, around the aperture of the 

 nostrils. The teeth are large and numerous, 118 or 120 being 

 usually present ; and the longest of the lower jaw are received 

 into notches in the upper, as in the Crocodile. The Gavial is 

 quite as aquatic in its habits, as is the Crocodile of the Nile ; its 

 hind-feet are fully webbed ; and the crest on the tail, increasing 

 the surface by which it strikes the water, is much elevated. This 

 powerful animal frequently attains the length of twenty-five 

 feet ; and is very formidable from its strength and ferocity. It 

 is very serviceable in devouring the numerous dead bodies of 

 men and animals, which are committed to the sacred river ; and 

 which would otherwise taint the air by their decay. Several 

 species of Crocodiles are found in a fossil state ; some of them 

 having been much larger than any now existing. It is interest- 

 ing to remark, that remains of forms allied to the Gavials are 

 found in the same strata with those of the Icthyosaurus and 

 Plesiosaurus ; which strata are, geologically speaking, much 

 older than those in which the remains of Mammals occur. It is 

 in these last, that we find relics of Sauria resembling the Cay- 

 mans of the present time ; and this is in accordance with the 

 general rule, that the terrestrial animals were the last to make 

 their appearance on the surface of the globe. 



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