40 0. C. Marsh—Notice of some new Fossil Mammals 
tains. The upper surface of this last lower molar is composed | 
of two transverse pairs of conical lobes, with a single posterior 7 
one on the median line. The anterior inner cone is larger than 7 
Measurements. : 
Antero-posterior diameter of last lower molar,_ 9° lines. § 
Greatest transverse diameter of same,----------------- 5 oe 
Transverse diameter between first and second pair of cones, 4°4 “ 
specimen on which this species is established was found ] | 
by the writer, in October last, in the Tertiary beds, on Henry's 7 
Fork, Wyoming. 
Platygonus Ziegleri, sp. nov. 
_The species is named for H. D. Ziegler, of Yale College, who 
covered the specimens on which the present description 18 
_ based. Phe losicy was at Grizzly Buttes, near the base of the 
