771 Extinct American Rhinoceroses and their Allies. [December, 
so also. Of the many mandibular symphyses from the Loup Fork 
formation which I have seen, none lack the canines and incisor 
teeth, so that it is probable that this character belonged to the 
two species above mentioned. A fifth species, the A. meridianus 
Leidy, I have provisionally referred here, on account of the 
similar character of the mandibular dentition; but its nasal bones 
and feet are unknown. Still another species, the A. jemezanus 
Cope, has been referred here, but on no other ground than that it is 
found in the same formation as the others. 
Specific characters ——The species above named all present well- 
marked cranial or dental characters, or both. But it is important 
to take into consideration the general structure of the skeleton. 
Fic. 7.—Aphelops malacorhinus Cope, skull one-sixth natural size, restored 
behind from another cranium. 
A, megalodus, the A. fossiger (of this paper), and the A. madacor- 
hinus and find distinctive characters present in nearly all their 
bones which I have observed. The A. malacorhinus is a com- 
paratively long-limbed animal, and its apparent elevation was in- 
creased by the shortness of the body, and especially of the neck. 
There was probably a great development of the upper lip, or 
snout, and the face was concave in profile. The A. megalodus was 
somewhat intermediate in proportions between this species and the 
A. fossiger Its limbs were shorter than in the A. malacorhinus, and 
the neck was longer. The feet were more slender. The A. fossig. 
had still shorter legs, and the length of the neck was about as in 
A, matacorhinus. In its form it must have been like a Avppc- 
potamus. Its limbs, and especially the feet, were very robust. 
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