1889.] NATURAL SCIENCES OF PHILADELPHIA. 225 



below the bead. The upper two-thirds of the shaft is trihedral, the 

 lower portion is compressed and oval in section. The distal end is quite 

 peculiar; it is less expanded transversely than in Cryptoproeta ; the 

 internal malleolus is long and very heavy and projects somewhat in- 

 ward as well as downward, and the lower end is abruptly truncate. 

 The sulcus for the tibial tendons is double, as in the felines, and the 

 bounding ridges are continued to the end of the malleolus. The 

 astragalar surface is much flattened and the intercondylar ridge is 

 hardly indicated, being formed merely by the angle at which the two 

 facets meet. This region of the tibia is strikingly different from the 

 corresponding part in Proailurus (see Filhol, No. 4, PL 5, fig. 6) in 

 which the groove for the astragalus is much more complete. On the 

 other hand, it is very similar to the distal end of the tibia in 

 Archcelurus (Cope, No. 2, PI. lxxia, fig. 15a). 



The fibula is comparatively well developed and very cat-like ; the 

 proximal end is considerably expanded from before backwards and 

 at the same time thickened ; it bears a large, oval and obliquely 

 placed facet for the head of the tibia. The shape of this part of the 

 bone is much like that seen in many viverrines. The shaft, thouerh 

 slender, is quite as strong proportionately as in the existing cats and 

 civets, and is of an irregular trihedral shape, with a sharp crista 

 iuterossea. The distal end is more expanded in both directions than 

 the proximal and in shape resembles that of the cats ; on its posterior 

 border is a deep tendinal sulcus, and on the inner side is a large facet 

 for the external face of the astragalus. The fibula is in contact with 

 the tibia only at the proximal and distal ends, the shafts of the two 

 bones being quite widely separated throughout their entire length. 



The Pes. 



The hind-foot is relatively long and slender and has many points 

 of resemblance to that of Cryptoproeta, as well as important differ- 

 ences from that animal. The calcaneum is very like that of Proai- 

 lurus and has considerable resemblance to the calcaneum of Procyon. 

 The tuber is short and stout, with a moderately expanded free end, 

 which is grooved by a tendinal sulcus ; the posterior astragalar facet 

 is large, regularly arched from before backwards and presenting de- 

 cidedly more internally than superiorly, in this respect resembling 

 Proailurus rather than Procyon. The sustentaculum is heavy and 

 prominent and the articular facet is reflected over upon the posterior 

 side ; the cuboidal facet is oval and concave, and slopes from within 

 outwards and downwards. The outer side of the distal end of the cal- 

 16 



