A NEW PALEOCENE MAMMAL SIMPSON 



as in A. sectorings ^ more triangular than in that species but less 

 transverse than in A. gilUanus. Base of hypocone projecting much 

 farther internally than base of protocone. Hypocones, especially 

 that of M ^, relatively stronger than in other species. Trigons, 

 proper, strongly compressed transversely. Anterointernal cingulum 

 (protostyle) very weak or absent. Small metaconules on all molars, 

 protoconules very weak or (probably) absent on M ^~^ Paracone 

 and metacone well separated, paracone larger than metacone, slightly 



FiGDRB 1. — Anisonchus fortunatus, new species, type specimen, U.S.N.M. 

 No. 12147. Left lateral view of face, with canine and P— M', and 

 crown view of left P'-M'. Teeth in part a composition from both 

 sides of original 



on M ^-2, more so on M ^ P ^ trigonal, wider than long, strong 

 internal heel. 



Measurements. — M ^-^ about 13.5 mm. Posterior edge of canine 

 to posterior end of M ^ about 30 mm. 



Remarks. — The diagnosis, in conjunction with what is known 

 of the San Juan Basin species, gives an adequate conception of the 

 known morphology of the cheek teeth. The canine is relatively large 

 and laniary, the incisors apparently small and unspecialized. The 

 snout was pointed, the nasals long and narrow. The very stout 

 zygoma arises chiefly outside and above M-. The anterior border 

 of the orbit is above the anterior end of M\ The general aspect of 

 the facial part of the skull is that of a small and primitive carnivore. 



This specimen fortunately preserves characters diagnostic of the 

 genus Anisonchv^: P^ with laterally compressed external cusp and 

 well-developed internal cusp, upper premolars in general enlarged 



