TERTIARY ANIMALS. 



533 



of Wyoming and deposited in the Museum of Yale College, where they 

 have been carefully studied. 



The type genus of this order is the Dinoceras. Almost every bone 

 in the skeleton of this animal is now known. Although elephantine 

 in size, there is no evidence in the skull of the existence of a proboscis ; 

 the proportions of the neck and fore-limbs, furthermore, show that 

 its presence was unnecessary. Three pairs of horns are indicated by 

 the projecting cores (Fig. 911), one pair of which stood far in front 

 on the nasal bones, another on the maxillary bones immediately above 

 the canines, and a third and much larger pair farther back on the 

 parietal bones. This last pair were sheathed with a thickened integu- 

 ment, which may have developed into true horn, as in the Prong-horned 

 Antelope. The three pairs of elevations are present in both sexes, but 

 proportionally smaller in the females. In addition to these formidable 

 weapons, both sexes were provided with canine tusks, those of the males 

 being very powerful, in some cases seven or eight inches in length. 



The largest, most specialized, and latest of the Dinocerata was the 

 huge monster Tinoceras. The head of this animal was four feet in 

 length, and the horn-cores much longer than in Dinoceras. Fig. 912 

 is a restoration by Marsh of this magnificent animal. 



Fig. 912.— Kestoration of Tinoceras ingens, x ^ (after Marsh). 



' The animals of this entire order seem to have been quite abundant 

 for a short time during the latter part of the Middle Eocene. They 

 then became extinct, leaving apparently no successors, though possibly 

 the Elephant tribe of to-day may be their greatly modified descend- 



