NOTES ON THE CANlDvE OF THE WHITE KIVER OLIGOCENE. 395 



prominence and, as in Daphcenus, it carries a subcircular facet for the astragalus ; in the 

 modern genus this surface is narrower and more elongate. The sustentaculum also agrees 

 with that of Daphcenus in not being so obliquely placed, with reference to the long axis 

 of the calcaneum, as in the existing members of the family. On the plantar side, 

 between the sustentaculum and the body of the bone, is a groove, the sulcus flexoris hal- 

 lucis, which is better marked in Cants than in either of the White River genera. This 

 is curious, in view of the fact that the latter possess a well-developed and functional 

 hallux, while in the former this digit is reduced to the merest rudiment. In Cams we 

 find a third facet for the astragalus, a small plane surface distal to the sustentaculum, 

 from which it is separated by a narrow sulcus ; continuous with this accessory facet, but 

 at right angles to it, is a small facet for the navicular. Neither of these articular surfaces 

 is to be found in Cynodictis. The facet for the cuboid, which in the recent dogs is almost 

 plane and semicircular in shape, is quite deeply concave and of nearly circular outline. 



The cuboid is relatively high and narrow, differing from that of Cards principally 

 in the smallness of its transverse and dorso-plantar diameters. The proximal surface is 

 occupied by a large facet for the calcaneum, which, as in Daphcenus, is much more con- 

 vex than in the existing dogs. The hook-like projection from the plantar side, which in 

 Daphcenus is very large and prominent and in Ccvnis is even more massive, in the present 

 genus is quite inconspicuous and is continuous with the projection from the fibular side 

 which overhangs the deep tendinal sulcus. The astragalar facet is small and is confined 

 to the dorsal side of the cuboid, being much less extensive than in Daphcenus. The facet 

 for the navicular is not so prominent as in Canis or even as in Daphcenus, and is con- 

 tinuous with that for the ectocuneiform. The distal end of the cuboid resembles that of 

 Daphcenus in having quite a concave facet for the head of the fourth metatarsal, while 

 that for the fifth is lateral in position. In Canis, on the other hand, the surface for mt. 

 iv is almost plane and that for mt. v occupies an entirely distal position ; the plantar 

 portion of the facet for mt. iv is much narrower than in the two White River genera, 

 and has thus quite a different shape and appearance. 



The navicular is almost a miniature copy of that, of Daphcenus and presents the 

 same differences from that of Canis. Seen from the proximal end, it is of more regularly 

 oval shape and is less contracted on the plantar side than in the modern genus. The 

 position of the navicular in the tarsus is likewise different. In Canis this bone has been 

 somewhat rotated, so that its principal diameter is the dorso-plantar one, and on the 

 plantar border it has been brought into contact with the calcaneum, for which it has 

 acquired a special facet. It is of interest to observe that a, similar but more extensive 

 rotation of the tarsal elements has been carried out in the horses, as Rutimeyer has 

 shown. In the White River genera, on the other hand, the principal diameter of the 



