Geology and Paleontology. . .) 92 
cture of Dinictis, which induces the authors to refer that _ 
is to the Cryptoproctide. 2. Determination of the foot- 
ture of Hoplophoneus, which places the genus in another 
; on. 
fe discovery of Metamynodon is an important addition to 
knowle it indi i i i 
CTO 
ars in the Eocene, in the genus Amynodon. The au- 
5 do not place these genera in the Hyracodontide, but pro- ` 
for them a new family. I, however, think that they cannot 
mynodon, according to Scott, the mastoid bone is exposed on 
€ Outer side of the skull, 
true line of ancestry of the rhinoceroses does not come 
‘ough the Hyracodontida, as. I showed in 1881." I then re- 
ded the genus Czenopus (Cope) as the ancestral form of the 
observed the Lophiodontid character 
+ occidentalis Leidy). Further observations to the same 
are made by Professors Scott and Osborn in the present 
- Ihave also noticed that the superior premolar teeth in 
Pus do not differ essentially from those of the Lophio- 
; dæ, and are totally different from those typical of Rhi- 
ontide and Hyracodontidz. : 
Laphie ri 
“Phiodonti 
the two a 
aa wearing, in consequence of the development of 
a ae crochets,” but the crests are essentially distinct. = 
è true i (type, A. iucisivum) the superior premolars are o 
on lmoceros type. In the Rhinoceros schleiermacheri they 
CO) tid pattern, 
tee Ceratorhinus, where I have placed it. 
S Amer, Philoso hi ; a eh he S stematic Ar- : 7 
eh phic. Soc., 1881, p. 380: “On t Y i 
s the order P eriosodactyla,” P ; . 2 
: S. Geolog. Survey Terrs., 1879, v. p. 235- 
Si ithe other hand, constructed, as in Canopus, on the eke 
This species must be, therefore, sepa- = 
randt has — 
