183 



covered with large osseous shields symmetrically arranged and highly orna- 

 mented. Other parts of the body, especially the ventral region, were pro- 

 tected by rectangular, ornamented shields, united to each other by suture. 

 The teeth are pleurodont, and are round with obtuse summits. The dorsal 

 and caudal vertebrae have the same general form as those of Varanus, but show 

 traces of a zygosphene articulation. 



Professor Marsh indicates eight species, mainly founded on differences in 

 the position, form, and ornamentation of the dermal osseous shields and the 

 form of the teeth. 



Dr. Carter has submitted to my examination a number of specimens col- 

 lected by him at Grizzly Buttes, which in part or whole are attributable to 

 the same genus, and mostly to the species named Glyptosaurus ocellatus. 



Several of the dermal shields from the trunk of the body are represented 

 in Figs. 13 to 15, Plate XVI, and several of the cranial shields in Figs. 16, 17, 

 of the same plate, all magnified two diameters. 



The dermal shields of the trunk are oblong quadrate, with the longer mar- 

 gins thick and roughened for sutural conjunction with one another. The ex- 

 tremities thin out for imbrication. The anterior extremity, which is over- 

 lapped by the shield in advance, extends a third or more of the length of the 

 plate, and is smooth. The posterior two-thirds or less of the shields are orna- 

 mented on their free surface with rounded knobs or tubercles, closely arranged 

 in more or less concentric rows. 



The cranial shields are from four to six sided, and proportionately. of greater 

 thickness than the former. All their margins are roughened for sutural at- 

 tachment together, and their free surface is ornamented in the same manner 

 as the shields of the trunk. 



Accompanying the specimens of dermal shields above described, there are 

 several detached vertebrae. One of the specimens is a dorsal vertebra re- 

 sembling those of Saniva, but somewhat smaller, and, like them, presents no 

 zygosphene articulation. It may probably belong to that genus. The other 

 specimen is an intermediate caudal vertebra of the same proportions of length 

 and breadth as in Saniva, but the ball and socket articulation is as high as it 

 is wide. It has no zygophene articulation, and the hypopophyses for the 

 chevron are immediately beneath the ball of the body. The length of the 

 latter inferiorly is 2§ lines. 



