NOTES ON THE CANID^ OF THE WHITE RIVER OLIGOCENE. 357 



Poebrotherium. In Daphcenus it is only the proximal portions of the two shafts which 

 are thus closely pressed together ; for the greater part of their length they are not in 

 contact, and thus preserve the primitive oval section. As their divergence is due to the 

 relative positions of the tarsal hones, there is no necessity for the lateral curvature of the 

 distal ends. The two metatarsals are very closely interlocked and in much the same 

 fashion as in Canis. On the head of mt. iv are two facets for mt. iii, of which the dorsal 

 one is a stout hemispherical prominence, which is received into the pit on the head of 

 mt. iii, already described. The plantar facet is actually upon the plantar rather than on 

 the tibial face of the bone ; the prolongation from the head of mt. iii extends around and 

 embraces this facet, and by means of the double articulation a very firm interlocking of 

 the two bones is effected. On the fibular side of mt. iv is a large and deep depression 

 which receives the projection from mt. v. The facet for the head of the latter is large, 

 slightly concave, and continues without interruption from the dorsal to the plantar 

 border, while in Canis there are two distinct and quite widely separated facets. The 

 shaft resembles that of mt. iii, but is somewhat more slender. In both of these meta- 

 tarsals the distal carina is jjlaced symmetrically with reference to the trochlea, but is less 

 compressed and prominent than in Canis. 



The fifth metatarsal is not completely preserved in any of the specimens, the only 

 representative of it being the proximal end, belonging to a large individual of D. vetus 

 (No. 11423). As the specimen is incomplete, nothing can be determined respecting its 

 length, but probably this was equivalent to that of mt. ii, the two forming a symmetrical 

 pair, much as in Dinictis, though mt. v, so far as it is preserved, seems to be somewhat 

 the stouter of the two. On the fibular side of the head is a very prominent projection, 

 ending in a roughened thickening, and directed obliquely outward and upward, the 

 " ascending process " (aufsteigender Fortsatz) of which Schlosser speaks in the passage 

 already quoted. In the recent dogs this process is very much reduced, while in Dinictis 

 it is of quite a different shape. In the Machairodont the process is a long and promi- 

 nent ridge, extending along the whole dorso-plantar thickness of the head, and projects 

 much more proximally than externally, while in Daphwnus it is a blunt hook which 

 projects more outward than upward. The Machairodont Hoplophoneus has the process 

 developed in very much the same way as in Daphcenus. 



The facet for the cuboid differs from that of Canis in being quite concave transversely 

 and in presenting as much toward the tibial side as it does proximally, while in the 

 modern genus the facet is small, plane, subcircular in outline and altogether proximal in 

 position. On the tibial side is a rounded protuberance which fits into the pit on the head 

 of mt. iv ; this protuberance is more prominent than in Canis and decidedly more so than 

 in Dinictis. What little of the shaft is preserved is transversely oval in section, with a 



