MOSASAURUS. 41 



and partly imbedded in its matrix, is sufficiently well preserved to exhibit its true 

 form. It presents considerable difference from that of the Mosasaurus of New 

 Jersey, as it does also from that of the Maestricht skull of the Paris museum. 

 It is of much greater breadth in proportion to its length, and is iu comparison very 

 abruptly narrowed at its lower part. Its height is three inches and a half, and its 

 extreme breadth above is equal. The width of the mandibular articulation is one 

 inch ten lines. The tympanic passage is proportionately larger, as is also the case 

 with its posterior overhanging process. 



The differences between this tympanic bone and that of the New Jersey, Mis- 

 souri, or Maestricht Mosasaurus indicate the Mississippi Mosasaurus to be a distinct 

 species. 



Cuvier^ observes, that very few bones of the extremities of Mosasaurus have been 

 found, and their rarity was such that, for a moment, he was led to doubt whether 

 the animal possessed limbs. He states that he was soon undeceived by recognizing 

 a bone of the pelvis which certainly belonged to Mosasaurus. The bone, considered 

 to be a pubis, resembling that of the Monitor, is figured in the Ossemens Fossiles. 

 Cuvier further says, that among some fossils from Seichem he detected a scapula 

 resembling that of the Monitor ; and subsequently received drawings from Maestricht 

 of a clavicle resembling that of a common Lizard, and also a coracoid bone. From 

 the specimens and figures Cuvier supposes the shoulder of the Mosasaurus to have 

 exhibited a close resemblance with that of the Lizards. After remarking that he 

 had been unable to procure any long bones of the limbs of Mosasaurus, he expresses 

 his vieAvs in regard to certain figures of bones, represented by Faujas-Saint-Fond^ 

 and Camper,'* reproduced in the Ossemens Fossiles. In regard to the figure of a 

 portion of an ulna, Cuvier observes, that if the bone belonged to Mosasaurus, it 

 would indicate the extremities to have been moderately elevated. 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 contracted fin, as in the Dolphins or Plesiosaurians. Of the 

 different bones of the feet, figured in the Ossemens Fossiles, after Camper, Cuvier 

 likens some of them to the principal carpal bones of the Crocodile, another appeared 

 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 his conjectures from mere figures, when the immediate comparison 

 of the bones 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 

 Cretaceous period of the Upper Missouri, which he views as the portion of a sca- 

 pula, a coracoid bone, and an olecranon process of the Mosasaurus. In relation to 

 the habits of the animal, he says, as it lived in the ocean the toes no doubt were 



* Ossemens Fossiles, Ed. 4, T. 10, pp. ITO-ITS. 



" Hist. Nat. de la Mont, de St. Pierre de Maestricht. ^ Annales du Museum, T. XIX. 



* Schadelbau des Mosasaurus ; Nov. Act. Acad. Caes. Leop. Carol. Nat. Cur., Vol. XXI, Pars 1, 



m. 



6 Aprn, 1865. 



