322 THE BHIDGEK IWUNA. 



Femur with a weak tliird trochanter. The proximal extremity of fourth 

 metatarsal of the right side furnishes instructive characters. The external 

 side is deeply excavated below the cuboid facet, to receive a correspond- 

 ingly prominent interlocking tuberosity of the fifth metatarsal. The exca- 

 vation is nt)t divided by a longitudinal groove, as in the cats, but its surface 

 extends continuously from front to rear. On the inner side of the fourth 

 there is a subvertical facet for the tliird metatarsal, which is bounded pos- 

 teriori}- by the usual deep vertical ligamentous groove. 



The foi-m of the true sectorial tootli, together with that of the meta- 

 carpal, approximate this genus to the Felidu' more closely than to any other 

 family of existing Carnivora. The resemblance seen in the sectorial is, 

 however, probably delusive, as it is not the same tooth as the sectorial of the 

 Cnniivora. The resemblance in the metacarpal is real, as the characters are 

 unlike those of Canidce or Hi/tenidoi. 



It is probable that this genus should be placed in the Ox^a?H/c?oE between 

 Plerodon and Oxyccna. But one species is yet known. 



Photopsalis tigrinus Cope. ^ 



American Naturalist, 1880, \i. 745; BuUotlu U. S. Geol. Surv. Terrs., vi, 1881, p. 193. 



Plate XXV 6, figs. 1-7. 



Size about that of the tiger or jaguai-, exceeding that of any other 

 flesh-eater of the Eocene period. The heel of the smaller tubercular- 

 sectorial is not large, and has a plano-concave superior surface. The prin- 

 cipal cusp is much elevated, while the internal cusp is small. The sectorial 

 (litters from that of a ////"//« in having the posterior cusj) more and the 

 anterior cusp less elevated; the lieel is only a strong posterior cingulum, 

 which is continued as a narrow line along the inner base of the tooth. A 

 rough cutting ridge forms the posterior inner angle uf the principal cusp. 

 There is a wide longitudinal groove of the inner face of the inferior canine, 

 whose enamel surface is impressed-punctate. The inner side of the crown 

 is so worn as to lead to the belief that the external incisor is of large size. 



The inferior border of the mandibular ramus rises below the last molar 

 tooth. The masseteric fossa shallows gi'adually below, so that its inferior 

 outline is not well defined. The dental foramen is of large size. The 



