198 



THE EXTINCT BATRACHIA, REPTILTA 



MOSASAURUS BRUMBYI, Gibbes. 

 Amphorosteus brwmbyi, Gibbes. Smithsonian Contrib. to Knowledge, [I. !) Tab.; Ill, 10—16, p. to. 



Vertebra of this species indicate a reptile of larger size than the M. depressus, and approaching the M. dekayi. 

 The position of the diapophyses is rather move anterior than to others, and. the centrum of the lumbars rather more 

 elongate than to any other speoies of the germs. The articular extremities are slightly oblique to the vertical diam- 

 eter. The animal appears to be not uncommon in the white cretaceous limestone of Alabama. It was first made 

 known by Dr. Gibbes, in his Memoir on Mosasaurus and its allies, to the Smithsonian Contribution, Vol. II. 



Inches. 



2.05 



2.8 



;s.25 



1.8 



Depth cup, 



Width " 



Length centrum, 



Edge ball to base diapophysis, 



Rotten Limestone, upper cretaceous Alabama. 



Species of Mosasaurus known only from teeth and cranial hones. 



MOSASAURUS CRASSIDENS, Marsh. 

 Silliman's Amer. Journ. Sei. Arts, 1870 (Feb., March). 



This species was established on a portion of the maxillary bone with teeth. The latter arc peculiar. The crown 

 of one, perhaps representative of all, is short, stout, of nearly circular section at the base and compressed towards the 

 apex. The latter is obtuse, and furnished on each side with a ridge, which together separate nearly equal faces, and 

 do not descend to the base. The apex is slightly rugose;; there are no lateral striie or facets. According to Marsh, 

 the maxillary bone is short and deep, and presents a considerable vortical external face. The remains indicate one 

 of the largest species of the genus. 



From the Cretaceous of North Carolina; discovered by Prof. Emmons, formerly State Geologist, Mus. Williams' 

 College, Mass. 



MOSASAURUS MINOR, Gibbes. 

 Loc. Cit. 7 Tab. I, 3-5. 



This small species appears to have been about as large as the Clidastes iguanavus, Cope. 

 The Cretaceous of Alabama. 



MOSASAURUS COPEANTJS, Marsh. 

 Mosa»auru> copeanut, Marsh, Proceedings Amer. Asso. Adv. Sci., 18(i(). Hillim. Amer. Journ. Sei. Arts, IH(ii), :'!•:;. 



The remains which at present represent fins species are portions of a skull with some of the maxillary teeth, and 



part of the corresponding lower jaws, Including the anterior extremity of the left ramus, and the articular surface of 



the left splenial bone. They indicate one of the smallest Mosasaui'oids yet discovered, and one very distinct from any 

 hitherto known. The teeth are slender, compressed, considerably curved, and deeply facetted. They are very 

 pointed, and a sharp ridge, without denfieulaflons, divides the outer from the toner BUrfaoes. The enamel of flu- 

 crown is remarkably smooth, and quite unlike the usual corrugated dental surfaces of the larger Mosasauroids. The 

 dimensions of a very perfect tooth from near the middle of the left lower jaw are as follows: 



Inches. .Lines. 



Length of crown and osseous support, l 11. 



Length of crown alone, 10.5 



Antero-posterior diameter of crown at base, 5.25 



Transverse diameter of crown at base, 4. 



