282 Annals of the Carnegie Museum. 



they are broader than long. Each shield is covered with small polished 

 tubercles without definite arrangement. From Bridger beds, Grizzly 

 Buttes, Wyoming. 



Glyptosaurus nodosus Marsh. 



American Journal of Science (3), I, 187 1, p. 458. 



Frontals thicker on median suture than those of Glyptosaurus 

 sylvestris. Shields between orbits very convex. The middle shield 

 on the frontals longer than wide and hexagonal. Length of animal 

 about three feet. From Bridger beds, Grizzly Buttes, Wyoming. 



Glyptosaurus oscellatus Marsh. 



American Journal of Science (3), I, 1871, p. 458. 



Cranial plates very thick and united by sutures, and having the 

 tubercles in concentric series. The outer row considerably larger 

 than the others. The next two or three rows considerably smaller, 

 and the inner rows very small, without definite arrangement. Larger 

 than Glyptosaurus sylvestris or G. nodosus. Bridger beds, Grizzly 

 Buttes, Wyoming. 



Glyptosaurus princeps Marsh. 

 American Journal of Science (3), IV, 1872, p. 302. 



Lower teeth close together. Bases deeply fluted. Frontal very 

 massive. Malar arch complete. Parietals thick with a parietal fora- 

 men. Length fully six feet. Bridger beds, Grizzly Buttes, Wyoming. 



Glyptosaurus brevidens Marsh. 

 American Journal of Science (3), IV, p. 305. 



Teeth rod-like, close together, and short, part of them barely 

 projecting from the jaw. Summits obtuse and marked by irregular 

 striae. Dermal scutes on malar region very thick, and heavy ; tubercles 

 in concentric rows. More than four feet long. Bridger beds, Grizzly 

 Buttes, Wyoming. 



Glyptosaurus rugosus Marsh. 

 American Journal of Science (3), IV, p. 305. 



Osseous scutes on frontals smaller than in Glyptosaurus sylvestris. 

 Prominently convex. Tubercles nearly equal in size, without definite 

 arrangement. Prefrontals and postfrontals approach more nearly to 

 each other above orbit. About three or four feet long. Bridger 

 beds, Grizzly Buttes, Wyoming. 



