254 O. C. Marsh—Notice of New Tertiary Mammais. 
incisor. The molar teeth have very short crowns, and are 
inserted by distinct fangs. The enamel is covered with a thick 
coat of cement. e molars are considerably worn, and the 
pattern of the enamel thus produced nearly resembles that in thé 
corresponding teeth of Anchitherium, with which the present 
teeth agree, also, in form and arrangement. The main pecul- 
larity of the upper molars is, that in all of them the anterior 
lake opens into the transverse valley, while the outer lake is 
distinct, and much contracted. The outer concavities of the 
external lobes are without any median elevation. The posterior 
inner cone is larger than the one in front. All the lower molars 
have an outer basal ridge. The middle teeth are the largest of 
the series. The second premolar resembles in form the same 
tooth in Anchitherium, but the anterior buttress is less distinct. 
There are six lower molars, the last premolar being the largest 
of the series. The first premolar had its anterior lobe unworn, 
and much elevated above the level of the grinding surface. 
a fore and aft diameter of the lower molars is unus sually 
. The enamel of these teeth is strongly rugose, more so 
ee that of the upper molars. 
Measurements. 
Space occupied by six upper molars,._.._...---.-------- 116 
Space occupied by three upper premolar --- oF 
a ee diameter of second boner - premolar, - Bey, 
reraverie Gintietee 505 ei a as 22° 
Antero-posterior diameter of last A oes molar, Pe Lr 
Transverse diameter, -__-._-- cian aah oe a eee 
Extent of three lower premo — 54 
Antero-posterior ne of first lower premolar, - - -- ---- 205 
seeovers Giabitler a 15° 
Antero-posterior oes of first lower true molar, -.---- !8° 
amv CrOe Grab ne 16° 
For the t type age we of the species, I am indebted to Rev. 
Thomas Con ee of Oregon, who first explored the Pliocene 
strata of that S 
‘ator brevidens, sp. nov. 
* Proc, Acad, Nat. Sciences, Philadelphia, 1868, p. 231. 
