328 NOTES ON THE CANTD.E OF THE WHITE RIVER OLIGOCENE. 



The upper molars are large and well developed, though the different species vary in 

 this respect, D. veins having larger tubercular molars than- D. hartshornian us. 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 

 ('69, PL I, Fig. 5). 



B. Low r ER Jaw t (PI. 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. %, 3 and 4, increase progressively in size and in the deA r elop- 

 ment of the posterior basal cusjds. 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 very characteristic of the genus, but well-marked specific differences 

 may be observed. In f D. dodgei the anterior triangle of the lower sectorial is of only 

 moderate height and the heel is but slightly concave, 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 concave 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 is a 

 tendency toward the formation of a talon with a single trenchant ridge, a tendency which 

 is fully carried out in the genera Temnoeyon and Hypotemnodon of the succeeding John 

 Day horizon. In all the species of Daphcenus the inferior sectorial is much more primi- 

 tive than in the typical modern Canidce, 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 Daphcenus have a close resemblance to 

 those of the creodont family Macidce, from which tins genus could hardly lie separated 

 upon the ground of the dentition only. 



