1880. ] Geology and Paleontoogy. 611 
America on account of the agreement of the species of the 
White River beds in dentition and absence of horn, with the A. 
incistvum of Europe. It seems now that none of the American 
species have the four digits in the manus, which is characteristic 
of Aceratherium, but that that member is three-toed, as in Aphelops. 
Even in the Eocene period, the most rhinoceros-like genus, 
Triplopus (Cope, this Journal, 1880, p. 383), was already three-toed. 
he lower Miocene species show in their superior incisor teeth 
that their position is between the two genera named. Triplopus 
probably has, like Hyrachyus, incisors $; the Rhinocerus occiden- 
talis of Leidy, ł, while in Aphelops Cope, they are t. In Peraceras 
Cope (this Journal, 1880, p. §40) superior incisors are wanting, 
he series of genera will ‘then be as follows. The table only 
differs'from the one already given in the NATURALIST (1879, p- 
771e), by the interjection of the two new genera named. The 
collateral genera are omitted. 
Calodonta 
Ja 
Rhinocerus. Atelodus. 
E 
Ceratorhinus. Peraceras. 
Poer 
Aphelops. 
| 
Cenopus. 
* 
Triplopus. 
The characters of Cenopus are as follows. Dentition; I. #; c. t3 
M. t; M$. Digits 3—3. The typical species is C. mitis (Acera- 
therium Cope).—E. D. Cope. 
A Genus tn Anticipation.—In a late number of the Revue 
Scientifique, M. Mortillet discusses the probable maker of the 
flints found in the Miocene deposits of Thenay, Cantal, and of a 
locality in Portugal. He rejects the proposition ef Gaudry that 
