WILLISTOX: NEW OR LITTI.F. KNOWN EXTINCT VKRTEl'.RATES. I7I 



restricted back of the orbits, where the transverse diameter measures 

 only 40 milliiueters, a little more than one-fourth of the entire width 

 of the skull. The occiput is narrow and high. 



The mandibular ramus is only moderately stout and its inferior 

 tlange is more produced than in any of its known contemporaries. 

 The masseteric fossa is deep, but the coronoid process is small and 

 vertical, much as in Hoploplwneus, and quite different from what is 

 figured in Pogoiioilon. The condyle is broad, but the outer part is 

 slender; the angle does not reach further back than the condyle and 

 terminates in a rounded extremity. Altogetlier, the small coronoid 

 process and the rather slender zygoma indicate less powerful temporal 

 and masseter muscles than one would anticipate for so powerful a 

 dentitional armature. 



The infraorbital foramen is large anil rounded and a little higher 

 than broad. Its i)osterior border is situated nearly over the anterior 

 basal lobe of the up[)er sectorial with the skull resting on the basi- 

 cranial plane. The condyloid foramen is large, and does not open 

 into the posterior lacerated foramen. Tiie otic bones have been 

 separated from the cranium, l)ut the grooves for the lacerated and 

 carotid foramina are shallow and separated b\- a low ridge. 1 can 

 find no post-glenoid foramen in either of the skulls. 



The sujierior incisors are smoothly conical and recurved, placed in 

 an even curve without cingula. The outer ones but little larger 

 and no longer than the inner ones. The superior canines are long, 

 recurved, and denlictdated on both margins below. The base of 

 the crown is a llattened oval; the posterior edge becomes thinner 

 below, but does not receive a cutting edge and denticulations for 

 more than an inch below the base of the enamel. Diastema back of 

 the catdnes equal to about twice the length of the third premolar. 

 Third premolar with a minute anterior basal cusp, the main cusp not 

 very prominent, the i)osterior lobe forming a straight, sharp, hori- 

 zontal cutting edge. Sectorial tooth large, with two prominent cusps, 

 which have been ground fiat on the inner side in the three specimens; 

 no anterior external or internal basal cusps, the internal, however, 

 represented by a root which is slightly convex; the anterior median 

 basal cusp small and tubercular. Molar larger than in the cats, partially 

 concealed by the posterior edge of the sectorial, placed nearly at 

 right angles to the longitudinal axis of the skull, implanted by two 

 roots (the crown is broken away on both sides). 



The lower incisors are broken off, but the basal portions show them 

 to be larger than the upper incisors, the outer one nearly as large 

 as the canine. The canine is conical, curved and pointed. Third 

 premolar rather small, with a less prominent cusp than in Felis; no 



