0. C. Marsh—New Tertiary Mammals. 207 
Limnotherium affine, sp. nov. 
A species of Limnotherium, somewhat smaller than L. tyran- 
nus Marsh, is well represented in the Yale Museum by portions 
of a skull with teeth, both lower jaws, and a considerable part 
of the skeleton of the same animal, The lower jaws are muc 
the base than the first lower premolar. This and the following 
premolar have each but one fang. The upper true molars closely 
Tesemble those of Thinolestes anceps. oe 
Measurements. 
Longitudinal extent of lower molar a. ea aaa a . 
Extent of last three lower rg Naeega area ee rece gene ear 17° 
Antero-posterior diameter of last lower WON ce o6 aoe big 
mermrerse ditmoter,.,..25 55 sii ee 1s eos 4° 
th of jaw on posterior face below last lower molar,... 9° 
Antero-posterior diameter of lower canine at DeRO ews <6 2°3 
€ type specimen of this species was found, last September, 
at Grizzly Buttes, by Mr. J. F. Quigley, of the Yale party. 
Orohippus pumilus, gen. et sp. Nov. 
consist of two separate series of upper molar teeth, four 
of each. They indicate a new genus of small solipeds, nearly 
allied to Anchitherium, and which ossibly nee include the 
1 racile. The crowns of 
ner tubercles, from which ridges extend obliquely to the an- 
_ letior inner margin of the outer cusps, but the anterior ridge is 
divided so as to form an intermediate anterior tubercle. All 
© teeth preserved have a distinct basal ridge. The species 
" &S about the size of Anchitherium gracile, and appears to have 
ad a long slender tail. 
Measurements. 
Vongitudinal extent of four upper posterior molars, ..... i ad 
Taeto-posterior diameter of last upper molar,.........+. 7° 
rensveree diamoter;..«s ¢ivsdcuki xs suaues eueeeds inne’ 8° 
aitero-posterior diameter of penultimate upper molar,.... 7°5 
‘Fansverse diameter, ....s+++++- iculb «Re CANCERS OREN ENS 8°5 
"he specimens here described were found, in August last, at 
Grizzly Buttes, Wyoming, by Mr. G. M. Keasbey and the writer. 
Helohyus plicodon, gen. et sp. nov. 
An interesting genus of small pachyderms, near!, related to 
Hyracotherium, is indicated by an upper molar tooth in perfect. 
