1889.] 



NATURAL SCIENCES OF PHILADELPHIA. 



227 



but there are important differences, chief among which are that in the 

 latter genus the inner condyle is 

 continued almost to the navicular 

 facet ; the external side is curved 

 outwardly very much more strongly 

 and the facet for the sustentaculum 

 is much smaller and further re- 

 moved from the head. 



The navicular is rather unusually 

 broad and of very simple construc- 

 tion ; the proximal surface is taken 

 up entirely by the deeply concave 

 astragalar facet; on the external 

 side there is a single narrow facet 

 for the cuboid, and the distal side 

 shows three facets for the cuneiforms, 

 that for the ectocuneiform beino- 

 much the largest, that for the en to- 

 cuneiform is very obliquely placed, 

 causing a great reduction of the 

 height of the navicular upon the 

 inner side. 



The cuboid is a stout bone with 

 large diameters in all three direc- 

 tions; the proximal surface, forming the facet for the calcaneum, is 

 somewhat convex and slopes downwards and outwards from the inter- 

 nal side ; internally to the calcaneal surface is a narrow and obliquely 

 placed facet for the astragalus. The internal face of the cuboid shows 

 a -ingle small and nearly flat facet for the ectocuneiform. On the 

 distal end there is a very large and slightly concave surface for the 

 fourth metatarsal, and external to this very much narrower facet for 

 the fifth metatarsal, which has an oblique position presenting out- 

 wards as well as downwards. The sulcus for the peroneal tendons 

 upon the external side of the cuboid is very distinctly marked, 

 though nut nearly so deep as in Procyon. 



The ectocuneiform is large, very broad on the dorsal side, espe- 

 cially distally and rapidly becoming narrower towards the plantar 

 side, where from the proximal end is given off a stout knob-shaped 

 process ; on the internal side is a pair of small facets for the second 

 metatarsal. The mesocuneiform resembles that of Paradox ur us in 



Fig. 5. A dorsal view of left calcaneum ; 

 Ai, plantar view of left astragalus of Din- 

 ictisfelina. In Ai, cb. marks the facet for 

 the cuboid. B, left calcaneum of Proaii- 

 urus ; C, of Cryptoprocta. B and C, 

 after Filhol. 



