XL TELEOSAURUS SUBULIDENS. 195 



We have also a nearly complete lower jaw, wanting the ter- 

 mination ; which differs from that of T. brevidens, in its slenderness, 

 being both narrow and shallow, in the greater proportionate length 

 of the symphysis, and in the greater number of the teeth, which 

 are thirty-one on a side, or, allowing four or five for the deficient 

 end, thirty-five or thirty-six, in all 140 or 144. Six teeth behind 

 the symphysis, twenty-five (or twenty-six) to the expanded beak, 

 and four for that part. Eleven slender, and mostly broken, teeth 

 in the sockets appear to be replacing teeth. 



The sockets for the teeth are remarkably round, and on the 

 whole nearly equal, and quite large compared to the teeth. 



Diagram LV. Lower Jaw of Teleosaurus subulidens. Scale one-tenth of nature. 



Of all known fossil reptiles the lower jaw of this small teleosaurus 

 bears the nearest resemblance to that of the Gangetic crocodile, 

 in the essential points of very long symphysis, and numerous long 

 slender teeth. The symphysis is more than half as long as the 

 whole jaw. 



The life of teleosaurus may be well judged by the proportions 

 and adaptations of his skeleton and dermal covering. Taking the 

 gavial for comparison, as of similar dimensions, we observe the 

 equally-prolonged jaws for seizing prey, more truly aquatic limbs 

 for steering, and equally powerful tail for swimming. Long, 

 slender, and active, well covered with armour plates, he must 

 have been formidable in the waters even when ichthyosaurs and 

 plesiosaurs were prevalent. These were not prevalent, it appears, 

 in the waters which were much resorted to in this part of the 

 ancient sea. Teleosaurus cannot have so frequently visited the 

 land as the modern crocodiles ; and it is in harmony with this con- 

 clusion thab his remains occur abundantly among the oolitic marine 

 animals, but not in the fluviatile or lacustrine deposits. About 

 eighteen feet may be admitted for the full length, and about half 

 a ton for the full weight of one of the largest of these carnivorous 

 sea-going crocodiles. 



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