0. C. Marsh—Notice of New Tertiary Mammals. 253 
mianiol groximal end coc. vacad .dieeh cao ern 
Width of articulation of distal end,.........-..------ 40° 
mength of third metacarpal, . 2... a<i.0+e4-s- ance 4: 180: 
‘Length of first phalanx of third metacarpal, ......-.-- 55° 
hength of second, phalanx, ._.. 02. co scc dae os cae ve 25° 
Length of third phalanx,_- ._-- = dean tee ea ae 38° 
Width of third phalanx,_.____. - : 50° 
sength of calceanedm,........ 
Length of astragalus,...._._. .--- od 
Length of third metatarsal,._..:.....--. -.---------- 208° 
The specimen here described was exhumed by the writer, in 
June last, from the Pliocene sands of the Niobrara River, 
Nebraska. 
Pliohippus robustus, sp. nov. 
limbs were shorter and stouter. The first upper premolar is 
much larger, and the upper molars are longer, and much curve 
The crowns of these teeth have a very similar arrangement of 
the enamel, but the folds are more complex. 
Measurements. 
Extent of four upper premglans.. 5. us. cee 93° mm 
Antero-posterior diameter of first upper premolar, - -- - - 18 
Antero-posterior diameter of second premolar, - ------- 29° 
Extent of three upper true mo OM, 31.52 oe 
Transverse diameter of humerus at distal end, - - -- ----- 54° 
Transverse diameter of radius at proximal end,. ------ 50° 
Transverse diameter of distal and. Se eee 50° 
Length of third metacarpal,...2.1.--.i------=+--«--- 178 
Width of proximal wid. > <5. 6520 scn i ee oe =e es 33° 
idth of distal articular face,....------------------- 29° 
Length of first phalanx of third metacarpal, - --------- as 
Length of third phalanx, .. . - 254002 -n24seee +e - res? 36° 
The known remains of this species were found by the writer, 
last summer, in the Pliocene strata of the Niobrara River. 
