I PROCEEDINGS OF THE ACADEMY OF 



and stouter than in the latter animal. Their lateral borders are much more 

 obtuse, and they terminate in a broad, thick, notched point. The ends bor- 

 dering the notch are most thickened and porous, apparently indicating the 

 attachment of a long moveable snout. The nasals do not rise from the fore- 

 head in the vaulted manner so conspicuous in Sivatherium and Rhinoceros, but, 

 as previously indicated, simply continue the curvature of the forehead. 



One of the most remarkable characters of the fossil is the greater extent 

 backward of the lateral nasal notch than in Sivatherium. In this it ceases far 

 forward of the position of the iorn cores, situated above the orbits. In the 

 Colorado fossil the notch continues back and beneath the position of the horn 

 cores, where the nasals apparently become continuous with the mamillaries. 

 The relative position of the orbits cannot be ascertained, as all the contiguous 

 parts are broken away. They appear to have been situated behind the posi- 

 tion of the horn cores. 



Several measurements of the fossil are as follows : 



Distance from the centre of the summit of one horn core to tke other. ..10j in. 



Length of horn cores above level of the intervening space 5 " 



Length of lateral nasal notch A\ " 



Distance from end of nose to centre of space between the horn cores.... 6 " 



Breadth of nose midway between end and position of horn cores 4 " 



Breadth of face, where narrowed, below horn cores ~i\ " 



It is probable that the fossil may pertain to the same animal as the remains 

 from the Manvaises Terres of Nebraska, described under the name of Titano- 

 therium, but in the state of extreme uncertainty as to its collocation, it may 

 with equal probability be referred to other genera, perhaps to Megalomeryx, 

 or it may have been an American species of the Sivalherium. Under the cir- 

 cumstances it may be referred to a new genus, with the name of Megacerops 



CoLORADENSIS. 



Prof. 0. C. Marsh, of Yale College, exhibited a number of vertebrae of a 

 new Dinosaurian from the cretaceous green sand near Barnsboro', N. J. He 

 observed that they indicated a reptile allied to Iladrosaurus Foulkii Leidy, 

 but only about one half the size of that species. The specimens, although 

 all found in the same immediate neighborhood, were apparently portions of 

 three different individuals, only one of which was fully adult. They con- 

 sisted of several dorsal and lumbar vertebrae belonging to the Museum of Yale 

 College, and an anterior caudal vertebra recently presented to the collection 

 of the Academy by Dr. Leidy. These remains appear to be quite distinct from 

 those already described, and apparently belong to the same species, for which 

 Prof. Marsh proposed the name Iladrosaurus minor. Prof. Marsh also showed 

 the tooth of a new and very large Mosasaurus from the cretaceous of North 

 Carolina. It belonged to a very perfect right upper jaw, formerly in the col- 

 lection of the late Dr. Emmons, and now in the cabinet of Williams College. 

 The teeth of the specimen are remarkably short and thick, nearly round at 

 the base and their surface entirely without facets. The remains preserved 

 indicate a species of great, size, probably sixty feet in length, but with a head 

 and muzzle comparatively short. It was named Jlosasattrus crassidens. 



A peculiar caudal vertebra of a somewhat similar reptile from the lower 

 cretaceous marl bed, near Hornerstown, N. J., was likewise exhibited. It is 

 oue of a series in the museum of Yale College, and indicated a new Mosasaurus 

 of medium size, apparently belonging to the genus Leiodon. The articular 

 surfaces for the attachment of the chevron bones were in nearly the same 

 plane as the lower surface of the vertebra^, and not impressed as in Macrosaurus 

 prorigerand other allied species The presence of well developed diapophyses 

 in this part of the caudal series was another peculiarity of these vertebrae, 

 and indicated that the animal had a broad, muscular tail. The species was 

 therefore named Leiodon lalicaudus. 



Prof. Marsh stated in this connection that in the November number of Silli- 



[Jan. 



