E. L. Troxell — American Bothriodonts. 331 



Other features, shown by this completer skull, mil 

 serve to establish the genus more broadly. M^ is nearly 

 equal to M'^ and has the same form; M^ is slightly 

 smaller ; the cusps of P* are not tall but the deuterocone 

 is broad at the base, the anterior and posterior sides of 

 the tooth are symmetrical ; P^ is very broad anteriorly and 

 squared, and the inner shelf is weak; a strong postero- 

 exterior fold constitutes the tritocone ; P^ is oblong due 

 to the very wide anterior edge and the absence of an inner 

 shelf or deuterocone. The absence of diastemata around 

 P^, the shorter, broader face, and the position of the 

 posterior nares opposite M^ are very distinctive of the 

 species and probably of the genus. 



Elomeryx Marsh. 



(Fig. 4.) 



Genoholotype, E. armatus (Marsh). Upper Oligocene (Protoeeras beds), 

 Hermosa, South Dakota. 



The species E. armatus Marsh was first described under 

 Heptacodon Marsh as follows •}^ 



"Figure 2 [our fig. 4] . . . represents natural size the last 

 right upper molar of another large ungulate mammal, the exact 



Fig. 4. — Elomeryx armatus Marsh, Holotype. Cat. No. 10176, Y. P. M. 

 CroTvu view of upper molars and premolars. X l/^- 



affinities of which can not now be determined. This tooth is con- 

 siderably worn, showing that it belonged to an old animal. The 

 remaining molars and part of the premolars in the same series 

 are preserved, and with them a very large canine still in position 

 in the jaw. All are worn, but otherwise in good preservation. 

 The tooth figured has a crown composed of five main cusps, the 

 antero-median being the smallest. The outer buttresses are of 

 moderate size, and there is none at the posterior angle. The 

 enamel of this tooth and of all the series is rugose. The true 

 molars differ greatly in size, the first being quite small, the sec- 

 ond intermediate, and the last equal in bulk to the two others. 



''The last premolar has one outer and one inner cusp. The 

 next tooth in front is larger, and has a triangular crown, and the 

 next is close to it. The canine is very large, dependent, and oval 

 in section. Behind it is a long diastema. " 



" 0. C. Marsh, This Journal (3), 48, 93, 1894. 



