246 O. CQ. Marsh—New Tertiary Mammals. 
side of upper premolars. No postorbital process. Third tro- 
chanter distinct. Type B gigas Marsh. 
4, Anisacodon Marsh, gen. nov. 
— 3 : 1 4 3 
Dentition =Incisors = ; canines +; premolars 3° molars ~. 
No superior diastema. Strong inner basal ridge on upper pre- 
molars. Last upper molar with two inner cones. No postor- 
bital process. T'ype A. montanus Marsh. 
. Anisacodon montanus, sp. Nov. 
This species is especially distinguished by the emargination 
of the extremity of the nasals; the short premaxillaries; and 
the rectangular form of the last upper molar. The inner pos- 
terior cone of this molar is smaller than the one in front, and 
quite distinct from the posterior basal ridge. 
Measurements. 
Extension of premaxillaries in front of canines, _--- ----- 
Distance from end of premaxillaries to narial aperture,-. 76° 
Width of nasals above end of premaxillaries, 5 
Antero-posterior diameter of last upper premolar, 
é 
OD TRO duck ks bids ccananie 
Antero-posterior diameter of penultimate upper molar,.. 77 
Transverse diameter,..............._-.- aS SSN ee 85° 
Antero-posterior diameter of last upper molar, - - ------- 84° 
meepeverse Geueuer, ooo ee 88° 
The specimen here described was found by the writer im 
November last, in the Miocene of northern Nebraska. 
Diplacodon elatus, gen. et sp. nov. 
and bones of the extremities. From the Eocene Limnohydie, 
already described, this genus is sharply distinguished by the 
last upper premolar, which has two Fistinet inner cones, thus 
agreeing essentially with the first true molar. This character, 
which has suggested the name of the genus, is one step tow 
the modern type of Perissodactyl dentition. The dental formula 
of the genus is the same as Limnohyus, viz: 
. 3 ‘ 1 3 
Incisors 3? canines +, premolars 7 molars > 
In other respects the teeth most resemble those of the Bron- 
