330 E. L. Troxell — American Bothriodonts. 



the orbit. The nasals are elongate, narrow in front, and widely- 

 expanded behind where they join the frontals. They touch the 

 lachrymals, thus separating the maxillaries from the frontals. 



' ' There were in all forty-four teeth. Three incisors were pres- 

 ent on each side above, and there is a diastema behind the last 

 one. The upper canine was large, and directed well forward and 

 outward. There is no diastema behind the canine, and the four 

 premolars form with the true molars a continuous series. The 

 first and second premolars are secant, the third is subtriangular 

 in outline, while the fourth has its crown composed of one ex- 

 ternal cusp and one internal cone. . . . 



''The posterior nares open opposite the middle of the last 

 upper molars. The anterior palatine foramina appear to be con- 

 fluent, forming together a heart-shaped aperture, which may in 

 part be due to injury. ' ' 



Fig. 3, — Octacodoji riihliceps (Marsh). Holotype. Cat. No. 10194, 

 Y. P. M. Palatal ^ie^v of skull. X 1/3- 



In so far as M^ of this specimen (see fig. 3) has low 

 cusps, weak cingula, general smoothness, failure of 

 transverse valley to cut into the mesostyle — showing a 

 ridge instead, a great anterior diameter, and especially 

 by its general contour, it is seen to be very closely related 

 to the type of Octacodon Marsh, to the exclusion of 

 other genera. 



The differences are minor, comparatively, but are suf- 

 ficient to distinguish the two species : of 0. gibbiceps we 

 note the weaker styles without sharp separation, the faint 

 cingulum both outside and back of the hypocone, the 

 less deep valleys, and the strong ridge from hypocone to 

 the center of the tooth. 



