192 WATER REPTILES OF THE PAST AND PRESENT 



gavials. In some forms the teeth are cylindrical and slender 

 throughout, and there may be as many as fifty on each jaw, or 

 two hundred in all; while in others only the anterior teeth are 

 cylindrical and the posterior teeth are flattened and serrate along 

 their cutting edges. In the body not very great differences have 

 been observed. Some are more slender than others, and there are 

 minor differences in the shapes and sizes and numbers of the bony 

 scutes along the back and on the throat. 



But they are all alike in their essential characters, a very long 

 beak with numerous teeth; the foremost ones on the expanded, 

 more or less spoon-shaped front extremity, are more or less, some- 

 times greatly, elongated. The jaws may be likened to a long and 

 slender pair of tongs with nipping teeth at the front end. The 

 strong, long, and flattened tail is sufficient evidence that the phy- 

 tosaurs were excellent swimmers, but, aside from that and the 

 posterior location of the external nostrils, directly over the internal, 

 few other aquatic adaptations are observed in the skeleton. There 

 are no sclerotic bony plates about the eyes, or at least none have 

 so far been discovered, although among the numerous known speci- 

 mens they would confidently be expected were they really present 

 in the skeleton; and the presence of bony armor negatives markedly 

 aquatic habits. 



Doubtless on the whole the habits of the phytosaurs were not 

 very unlike those of the modern gavials, which they so strongly 

 resemble in form, size, and general characters. But they differ 

 very greatly from the gavials in the extreme posterior position of the 

 nostrils, and in the greatly elongated teeth of the front end of the 

 beak, teeth which must have had some especial and peculiar use. 

 Nor is the position of the nares to be accounted for satisfactorily 

 by reference to aquatic habits. It has been suggested that the 

 creatures used the very long and slender beak in prodding and 

 probing in the sand and mud for soft-bodied invertebrates, worms 

 and the like, for which the teeth would be especially fitted; and 

 that the posterior position of the nostrils may be in part, perhaps 

 wholly, accounted for by this habit, which permitted the reptiles 

 to breathe without extricating the beak from the mud or shallow 

 waters. That the animals were whollv and intenselv carnivorous 



