350 NOTES ON THE CANIDE OF THE WHITE RIVER OLIGOCENE. 
very large, forming an oval, with its long axis directed antero-posteriorly, in shape and 
size agreeing much more closely with the condition found in the cats than with that of 
the recent dogs. 
The femur (Pl. XX, Fig. 18) is stout, and long in proportion to the length of the 
fore-limb bones, but not very long as compared with the size of the animal. While not 
differing in any very marked fashion from the thigh-bone of Canis, it yet has some 
resemblances to that of the felines. The small, hemispherical head is set upon a longer 
neck than in recent dogs and has a smaller, deeper and more circular pit for the round 
ligament, than in the latter. As in Canis, the head projects more obliquely upward and 
less directly inward than in Felis. The great trochanter is large and has a very rugose 
surface, but it has no such antero-posterior extension, does not rise so high and is not so 
pointed as in the existing forms of Canide. In consequence of this shape of the great 
trochanter, the digital fossa is smaller and much shallower than in the cats or recent 
dogs. From the great trochanter a sharp and prominent ridge, the linea aspera externa, 
descends along the external border of the shaft. Whether a third trochanter was present 
cannot yet be definitely determined, because in the only two femora preserved in the 
collection, the outer edge of the shaft is broken away at the point where the third 
trochanter would be, if present. In all probability, however, Daphenus did possess this 
trochanter, at least, in rudimentary form, as may be inferred from the analogy of the 
sabre-tooth Dzinictis, and still more from the little contemporary dog, Cynodictis, which 
in many respects approximates the structure of the modern Canide more closely than 
does Daphenus. The lesser or second trochanter is larger, more prominent, and of more 
decidedly conical shape than in the recent species of either Canis or Felis. 
The shaft of the femur is long, slender and nearly straight, though slightly arched 
toward the dorsal or anterior side; it differs from that of the modern dogs in its lesser 
curyature, and in broadening and thickening more gradually toward the distal end, and 
from that of the true cats in being more slender and of more nearly cylindrical 
shape. The rotular trochlea is rather narrower transversely than in the true cats, 
or eyen than in Dinictis, but is characterized by the same shallowness, and resembles 
that of the latter genus in its shortness vertically and lack of prominence. Trans- | 
versely, the groove is but slightly concave, and it has much less prominent borders 
than in the existing species of Canis ; these borders are slightly asymmetrical, the external 
one rising a little higher and being a trifle more prominent than the internal. A decided 
difference from both Canis and Felis consists in the fact that the trochlea hardly projects 
at all in front of the plane of the shaft, the anterior face of the latter gradually swelling 
to the level of the groove. In both of the recent genera mentioned, and especially in the 
canines, the trochlea projects prominently in adyance of the shaft. 
