AND AVES OF NORTH AMERICA. 



181 



figures of bones, represented by Faujas Saint Fond and Camper, reproduced in the Osse- 

 in ens Fossiles. In regard to the figure of a portion of an ulna. Cuvier says, that if the bone 

 belonged to Mosasaurus, it would indicate the extremities to have been moderately ele- 

 vated. But he continues, the bones of the feet, so far as they are known, appear on the 

 contrary, to have belonged to a sort of a contracted fin, as in the Dolphins or Plesiosau- 

 rus. Of the different bones of the feetj figured in the Ossemens Fossiles, after Camper, 

 Cuvier likens some of them to the principal carpal bones of the Crocodile, another ap- 

 peared to belong to some huge Saurian, some are phalanges, and two are attributed by 

 him to Turtles, whose remains are not Less common in the deposits containing those of 

 the Mosasaurus. In conclusion Cuvier adds that, "it was not without hesitation that he 

 expressed the conjectures from mere figures, when the immediate comparison of the hones 

 themselves would scarcely suffice, so great is their diversity and so small the precision of 

 their forms in reptiles." 



Goldfuss describes and figures several bone fragments from the deposits of the Creta- 

 ceous period of the Upper Missouri, which lie views as the portion of a, scapula, acoracoid 

 bone, and an olecranon process of the Mosasaurus. In relation to the habits of the ani- 

 mal, he says, as it lived in the ocean the toes no doubt wen; webbed, hut the remains 

 which have been discovered, on the contrary, do not lead to the supposition that it pos- 

 sessed fins like Ichthyosaurians. Prof. Owen, alter remarking that no part of the organi- 

 zation of the Mosasaurus is so little known as that of the locomotive extremities, and sub- 

 stantially quoting the; views of Cuvier, expressed above, enters into the description of some 

 long hones of the extremities, "showing the Lacertian type of structure," which were ob- 

 tained in the Green-Sand formation of New Jersey. Prof. Owen says, "on the highly 

 probable supposition that; these; bones belong to the Mosasaurus, they indicate the ex- 

 tremities of that, gigantic Lizard to have been organized according to the type of the 

 existing Lacertilia and not of the Enaliosauria or Cetacea." Pictet says the humerus of 

 Mosasaurus is thick and short, like that of Ichthyosaurus, hut gives no evidence for this 

 assertion. He adds, we may conjecture, from the flattening of the bones of the members, 

 that the feet wen; probably converted into fins like those of the Enaliosaurians. 



Schlegel states in one of tin- older numbers of Leonhard & Bronns' Jahrbucb dor 

 Geologie, etc., that the anterior limbs are paddles, adapted to an aquatic habit. 



Finally, Leidy (Cretaceous Reptiles, 42,) states that " remains apparently of Mosasau- 

 rus which I have the opportunity of examining, indicate the limbs to have been fins, par- 

 taking in their structure of the characters of those of the marine turtle and the l'lesio- 



saurus." 



» 



'There can he no doubt that the above authors have correctly assigned such limbs to 

 the two species that came under their observation ; and I add the evidence derived from 



AMEttlOA. PH1L0. 800. — VOL. XIV. 4(> 



