Cope.) 
460 [Aug. 15. 
DESCRIPTIONS OF SOME NEW VERTEBRATA FROM THE 
BRIDGER GROUP OF THE EOCENE, 
By E. D. Cops. 
(Read before the American Philosophical Society, August 15, 1872.) 
MESONYX OBTUSIDENS, Cope. 
Represented by a large part of the skeleton of an individual of about 
the size of the wolf (Canis lupus). The lumbar vertebra display the 
short acuminate, and anteriorly directed diapophyses, characteristic of 
carnivora, while the astragalus resembles that of the same group. The 
claws are flat and not curved. The molar teeth exhibit two principal 
lobes and a thin rudimental at one extremity. The middle lobe isa com- 
pressed cone, the posterior, a cutting edge, but medially placed, and less 
acute than in Hyenodon, and the sectorial teeth of other carnivora, form- 
ing a less specialized cutting apparatus. The canines are well developed. 
A premolar is stout conic, with rudimental tubercle at base. 
we 
M. 
Length of a sectorial (crown).....-..++.+++5 Peet eee OLOLO 
Greatest width, .. Pie Ses OAL UIC Heike Canora eg vie 00S 
Elevation of crest Cane dpueieas .006 
Length of crown of a second....... CHOPS Mra eb tes O15 i 
AWICU ies for tee ba eG es ee ee as .0065 
Elevation of middle lobe............. ae Toe is . O14 
Length of crown Of GamanGie ees. a AEG UNE 026 i 
Dinniober Dear DASG.A ss ariel. eee e. pert Fee Onl: 
‘he number of the teeth cannot be determined, owing to the injured 
condition of the jaw bones. The enamel is entirely smooth. 
Found on the bluffs of Cottonwood Creek, Wyoming. 
TRIACODON ACULEATUS. Cope. 
Established on two teeth of the molar and premolar series. The molar 
is subtriangular at the base of the crown, one side being convex ; the op- 
posite angle nearly right, and the two remaining sides flat. The crown 
is divided into three elevated trihedral cones, one at each angle. Their 
adjacent angles are acute, and the angle of union is fissured, like the same 
point in the sectorial tooth of a carnivora. The smaller lobes are of equal | 
elevation, but the crown of one is expanded so as to be slightly spade- 
shaped. The enamel is smooth. 
Elevation of highest cusp... 
a“ ee BNONURI Ss Oe cat 4 3 
Long diameter base of crown... 
a ALO BUG sie cass aaa 
The premolar is smaller, with shorter cusps, and one of the laterals re- 
duced to a rudiment. 
This species is near the 7. fallax of Marsh, but the tooth he describes 
is narrower in proportion to its length, and has the anterior lobe little 
over half as high. 
