PHARSOPHORUS 



213 



of the talonid of the lower molars, which in Pharsophorus 

 have no basin and consist of a single cusp; and, lastly, in 

 the symphysis of the lower jaws being ligamentous, whereas 

 in the two preceding genera, it is fused. Pharsophorus 

 is probably ancestral to Borhyaena. In the case of Probor- 

 hyaena, only a mandible, with the canine and premolars 

 3 and 4 intact, has been found. The fourth premolar is 

 more reduced than in other genera, but, until more teeth 

 are known, its affinities can not be at all closely determined. 



U.m. 



Fig. 138. Diagram of a generalized upper molar, U.m., and a lower molar, L.m., of Borhynidae; 

 a.s., ant. style; hid., hypoconulid; ml., metacone; mtd., metaconid; pa., paracone; pad., paraconid; 

 Pr., protocone; prd., protoconid; Id., talonid. 



Pharsophorus Ameghino 



Pharspohorus Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 502. 



The genus was founded on a lower jaw with premolar 

 3 to molar 3 in position. We found beside the above an 

 upper jaw with premolar 3, and molars 2 and 3 complete 

 while premolar 4 and molar I are more or less fragmentary ; 

 from which the following generic characters may be made 

 out. The incisors are tiny; the canine very large, equal 

 to that of Borhyaena; the upper and lower premolars pro- 

 gressively smaller from front to back. Upper premolar 3 

 is a simple two-rooted tooth, the crown consisting of a 

 single blunt central cusp. On the upper molars the proto- 

 cone is not developed as a cusp, though the third inner root 



