370 E~. L. Troxell — Entelodonts in Marsh Collection. 



P 3 is touching P 4 ; the sides of the tooth are flat or slightly 

 convex, and the posterior heel is not especially wide. The 

 cingula are weak and the ridges wanting or worn smooth. 

 P 4 is shaped like that of the type of A. clavus clavus, ex- 

 cept that the sides are rounded, it is wider than long, the 

 cingula are less strong, and the tooth is relatively small. 

 M 1 is subquadrate, but the inner side is shorter antero- 

 posteriorly. 



M 2 is rounded but flat anteriorly. It has not the trap- 

 ezoid form like that of the type of the species. The base 



Fig. 7. — Archceotherium clavus darbyi, subsp. nov. Holotype. Cat. No. 

 10032. Palatal view of skull. One-fifth nat. size. E.a.m, external auditory 

 meatus; Eo, eustachian canal; Ec.f, external carotid foramen; F.h, hypo- 

 glossal foramen; F.l.p, foramen lacerum posterius; F.m, foramen magnum; 

 F.o, foramen ovale; I.f, infra-orbital foramen; O.f, optic foramen; Orb, 

 orbital foramen; P.f, palatine foramen; S.f, stylomastoid foramen. 



P, palatine bone; J, jugal or malar with its posterior process, P.j, occu- 

 pying a part of the glenoid cavity, G, of the temporal or squamosal. 



of the paracone is no larger than the base of the metacone. 

 M 3 is round or slightly oval, due to the strong lobes of the 

 para- and hypocones. There is a moderate cingulum an- 

 terior only, and no heel. The protocone is forward of the 

 mid-line. The hypocone is strong. (See cusp indica- 

 tions, figs. 17, 18.) 



The body of the ramus and the branches back to P 3 are 

 missing with the exception of one anterior mental tuber- 



