366 NOTES ON THE CANID# OF THE WHITE RIVER OLIGOCENE. 
nus. It is composed of the same elements as m4, but has a different shape, owing to 
the greater proportionate length, antero-posteriorly, of the inner portion of the crown. 
In appearance this tooth is a miniature copy of that of Canis. 
B. Lower Jaw.—The incisors are very small and closely crowded together, so that 
the fang of i 5 is pushed back out of line with the other two. 
The canine, which is even more compressed laterally than the upper one, is long and 
recurved ; it is separated from p ; by a very short diastema. 
The first premolar is a very small, simple cone, inserted by a single fang. The sec- 
ond is much larger and is supported by two roots; it has an anterior basal cusp, which 
is formed by the cingulum and is subject to considerable variation, being much larger in 
some individuals than in others. The third premolar has a high, compressed and sharp- 
pointed crown and bears three accessory cusps, anterior and posterior basal cusps formed 
by the cingulum, and a third developed upon the posterior edge of the protoconid, very 
much as in Canis. The fourth premolar is slightly larger than p 5 and has more dis- 
tinetly developed accessory cusps, but on both p 3 and p q these cusps are subject to much 
variation and in some specimens they are feebly marked or eyen absent. 
The European C. intermedius has very similar premolars to those of C. gregarius, 
and in both species the anterior basal cusps (which are not present in Daphenus) give a 
somewhat viverrine character to the dentition. 
The first molar has a quite elevated anterior triangle, with a high, pointed proto- 
conid and a well-developed paraconid, both of which are more compressed and trenchant 
than in Daphenus. The metaconid is smaller than in the latter and is placed lower 
down and more posteriorly, so that it is visible from the outer side, much as in the mod- 
ern dogs. The heel is basin-shaped and is composed of a large, crescentic external cusp 
and a smaller internal cusp. In the European species may be observed certain differ- 
ences in the structure of the lower sectorial from the White River form, though these 
differences are not great. In the Old World species the anterior triangle is higher and 
the protoconid less compressed, while the metaconid is larger and occupies a more ele- 
vated and anterior position; in other words, the anterior triangle resembles that of 
Daphenus. Another difference from the American forms consists in the presence of a 
second internal cusp in the heel of the sectorial, which may be observed in most of the 
individuals figured by Schlosser and Filhol. Howeyer, in a specimen of C. /acustris from 
Débruges, which the Princeton Museum owes to the courtesy of Prof. Gaudry, this sec- 
ond cusp is not visible. In perfectly unworn teeth of Daphenus hartshornianus a feeble 
indication of this second cusp may be seen. 
The second molar is tubercular and of a narrow and elongate oval shape ; in consti- 
tution it entirely resembles that of Canis; the paraconid has disappeared, while in 
