352 Structure of the Fossil Saurians. 



from the Gavial, Geoffroy also proposed, and to which he 

 assigned the name of Steneosaurus rostro-major, exhibits 

 little in common with the Gavial, except the general similarity 

 of the form of the head. The teeth stand in separate alveoli, 

 and are replaced in a vertical direction from within. A more 

 complete investigation of the teeth would be extremely de- 

 sirable. The beak is absolutely smaller than that of the 

 Gavial, and passes gradually into the skull ; in which respect 

 the forms of both differ very materially. The lower jaw 

 possesses 22 teeth, 14 of which are placed on the diverg- 

 ing rami, while the Gavial has but four teeth in this situ- 

 ation (two on each side). The rami also diverge at a much 

 smaller angle than in the latter animal. The skull pre- 

 sents, in the occiput and in the frontal bones, differences no 

 less striking. The eye was excessively large in comparison 

 with that of the Gavial ; and was placed not above in the skull, 

 but laterally, as in the Lacertae. The openings of the nasal 

 orifices lie, as in the Gavial, at the end of the beak. The 

 vertebral column is more contracted in the middle than in 

 Crocodiles. The vertebrae are distinguished by the very re- 

 markable peculiarity, that their anterior surface is convex, and 

 their hinder concave ; consequently, the reverse of those of 

 the Crocodiles, and formed like the cervical vertebrae of the 

 whole order of terrestrial Mammalia; for instance, the Ru- 

 minants and the Solipedes, in which, however, the processes 

 are different. The convexity of the anterior surfaces soon de- 

 creases in the fossil animal, and both surfaces become smooth. 

 Instead of the simple inferior spinous process, we perceive two 

 edges. I name this animal (whose structure is not adapted 

 to form a subgenus of the Crocodile), from the peculiar cha- 

 racter of its vertebrae, Streptosp6ndylus. In the collection 

 of the town of Caen, according to Geoffroy, the impression 

 of a complete skeleton is preserved. One there perceives a 

 phalanx of the hind foot, which is very similar to that of the 

 Dugong. Hence, these animals effected their locomotion in 

 a similar manner. It appears to have possessed only a mo- 

 derately sized middle claw ; and rudiments of lateral phalanges 

 are to be observed. 



Metriorhy'nchus. 



Cuvier's second Gavial of Honfleur ought no more to be 

 associated with the Crocodiles than the animal just described. 

 Geoffroy considers it as a species allied to the foregoing, and 

 names it Steneosaurus rostro-mmor. The few remains of 

 this creature which have yet been made known are sufficient 

 to convince us of the generic difference. The length of its 

 beak preserves the medium between that of the Gavial of the 



