328 NOTES ON THE CANIDZ OF THE WHITE RIVER OLIGOCENE. 
The upper molars are large and well developed, though the different species vary in 
this respect, D. vetus haying larger tubercular molars than D. hartshornianus. The first 
molar is, in general, like that of Canis, but differs in certain details. Thus, the two 
external cusps are more conical in shape, more nearly equal in size, and are not placed 
so near to the outer edge of the crown, resembling in this respect the upper molars of 
certain creodonts, such as Sinopa; the large inner crescentic cusp is much as in Canis, 
though hardly so prominent, especially in D. hartshornianus ; in D. vetus it is larger. 
The second molar is much like the first in shape and construction, but smaller and some- 
what simplified, the conules being minute or altogether absent. The third molar is very 
small and has a low, transversely oval crown, in which separate elements are not distin- 
guishable. This tooth is rarely preserved and none of the specimens at my disposal 
possess it, though the alveolus for it is almost always present; it is well figured by Leidy 
(Cosy Je Ih, lanes, 5) 
B. Lower Jaw (Pl. XIX, Figs. 5, 6,7). In none of the available specimens are 
the lower incisors sufficiently well preserved to be worth description. 
The canine is very much the same as in the recent members of the family. The 
premolars are somewhat more complex than those of the upper jaw. The first is very 
small and simple, while p. 5, 3 and j, increase progressively in size and in the develop- 
ment of the posterior basal cusps. In the more ancient and primitive species ? D. dodgei, 
from the Titanotherium beds, the premolars are lower, thicker transversely and less 
acutely pointed, and have larger posterior basal cusps than in the later species from 
higher horizons. In all the species these teeth are more widely separated than in the 
modern genera. 
The molars are yery characteristic of the genus, but well-marked specific differences 
may be observed. In ? D. dodgei the anterior triangle of the lower sectorial is of only 
moderate height and the heel is but slightly concaye, the outer and inner ridges (hypo- 
and entoconids) being very little raised. In D. hartshornianus the protoconid is high, 
narrow and pointed, and the talon is more concaye than in the first-named species, and 
has more prominent internal and external cusps. In D. vetus the inner cusp of the 
talon (entoconid) is reduced and, as Cope has already pointed out (84, p. 898), there isa 
tendency toward the formation of a talon with a single trenchant ridge, a tendency which 
is fully carried out in the genera Temnocyon and Hypotemnodon of the succeeding John 
Day horizon. In all the species of Daphenus the inferior sectorial is much more primi- 
tive than in the typical modern Canida, as is clearly shown by the higher and more 
conical protoconid, the lower and smaller paraconid and much less reduced metaconid. 
In fact, both the superior and inferior sectorials of Daphaenus haye a close resemblance to 
those of the creodont family Miacida, from which this genus could hardly be separated 
upon the ground of the dentition only. 
