E. L. Troxell — Entelodonts in Marsh Collection. 375 



Marsh type, the much greater transverse diameter pos- 

 terior of P 3 , the greater slenderness of the face, the 

 roughness of the enamel, and the much smaller size. 



Archceotherium sp. — This specimen is undoubtedly 

 Archceotherium, as shown by the double-rooted premolars, 

 and not Pelonax, but because of the great anterior tuber- 

 cles it resembles P. potens. The structure of its arch, the 

 wide, flat dependent process, the thick premolars, the 

 smooth teeth without heels, the general size, and the 

 rugose f rentals resemble A. clavus darbyi, subsp. nov. 



Aech^otheeitjm ceassum Geoup. 

 Archceotherium crassum (Marsh). 



Holotype, Gat. No. 12020, Y. P. M. Probably Cedar Creek beds (Middle 

 Oligocene) . Colorado. 



In 1873 Marsh described this specimen (fig. 9) which 

 was discovered three years before near Gerry's Ranch, 

 Colorado, in part as follows (1873, pp. 487-8). 



"A large suilline mammal, which probably belongs in the 

 genus Elotherium, is indicated by portions of two skeletons 5 in 

 the Yale Museum. These specimens present some features not 

 before observed in any Ungulates. The most striking of these is 

 a very long process descending from the malar bone, and giving 

 attachment to the masseter muscle. This process resembles some- 

 what the downward prolongation from the zygomatic arch in 

 some Edentates and Marsupials, but it is longer, and more com- 

 pressed. The radius and ulna were separate, or very loosely 

 united. The third and fourth metacarpals were nearly equal in 

 size, and the second and fifth larger than the corresponding bones 

 of the pes. In the latter the first digit was wanting, and the 

 fifth rudimentary. The hoof phalanges were short. The tail 

 was long, and quite slender. This species is intermediate in size 

 between E. mortoni and E. ingens. 



1 ' Measurements. 



mm. 



Length of malar process below squamosal suture 130.0 [174]* 



Length of symphysis of lower jaws 7 144.0 



Antero-posterior diameter of lower canine 32.5 



Transverse diameter 28.5 



Transverse diameter of humerus at distal end 81.0 



Transverse diameter of radius at distal end 75.0 



Transverse diameter of head of tibia 81.0 



Length of third metatarsal 8 102.0 ' ' 



5 The " rather smaller specimen" mentioned is treated on a later page,, 

 being the paratype, Cat. No. 10036. 



6 The measurement of 130 mm. should be about 174 mm., due to the fact 

 that the tip of the bone is now in place. 



7 This measurement was undoubtedly from specimen No. 10037, doubt- 

 fully of the same individual. 



8 This length of 102 mm. for the third metatarsal is an impossibility. 



