SLES Spa ee Gee ee PSI SR nT alo DEE GY DE VER i” gE aoe EAB) Peano ym 
1884.] The Creodonta. 351 
Cope (Fig. 13). It has compressed premolars, except the fourth 
superior, which is conic with two basal lobes. In Proviverra 
Riitimeyer, this tooth is triangular and cutting. One species has 
been found in the Swiss Eocene. Quercitherium of Filhol is dis- 
tinguished by its very robust premolars. Like Proviverra it has 
but one rather small species. It is from the French Phosphorites. 
Stypolophus has the two cusps of the superior true molars close 
together, forming twin cusps, and they have behind them a heel, 
which is cutting. Two species have been discovered in the 
French Phosphorites, one of which, the S. cay/usi of Filhol, is 
preserved to us in the most perfect skull of a Creodont known. 
From it I have restored the skull of the S. whitie (Fig. 13). It 
has elevated sagittal and posterior crests for the insertion of the 
temporal muscles, and the brain-case is very small. A cast of the 
brain displayed to Mr. Filhol the following characters: The 
hemispheres are small, and leave the cerebellum and the posterior 
edge of the middle brain uncovered. Anteriorly they contract to 
an isthmus which separates them from the large olfactory lobes. 
The hemispheres display three longitudinal convolutions, and 
kod little indication of sylvian fissure. Of the American spe- 
asa five are known from the Wasatch, and four from the Bridger 
Nearly allied to Stypolophus is the genus Didelphodus Cope, 
which only differs from it in the posses- 
sion of but three superior premolars. 
The single species, D. absaroke Cope, 
ts about the size of a skunk, and has 
o obtained in the Wasatch Eocene 
Bs of the Big Horn river, Wyoming 
18. 19), 
| aa 
this respect Esthonyx esembles some of the genera of 
