80 Annals of the Carnegie Museum. 



Cope, while No. 3183 is somewhat smaller. These specimens are 

 easily separated from the type of Achcenodon robustiis Osborn by 

 their slenderer and shallower form and by the relatively longer molars. 

 Furthermore the heel of P^ in A. insolens, as exhibited by the Car- 

 negie Museum specimen No. 2309 (see Fig. 11) is more strongly de- 



FiG. II. Achcenodon insolens. Carnegie Miiseun, No. 2309. X 1/4. 



veloped than in A. robust us. The premolars in A. robustiis are appar- 

 ently larger than in A. insolens, which, however, may perhaps be 

 partly due to imperfection of the premolar teeth in No. 2309, which 

 are extensively repaired with plaster. The coronoid process of A. 

 insolens appears to be more everted and the summit sharper than in 

 A. robustus. 



Both of these mandibular rami were found by Mr. Earl Douglass in 

 Horizon B of the Uinta sediments. 



20. Achaenodon uintense (Osborn). 



Bull. Amor. Mus. Nat. Hist., Vol. VII, 1895, p. 102. 



This species is represented by two crania, C. M. Nos. 2160 and 3182, 

 found by ]\Ir. Earl Douglass in the same horizon (B.) and locality 

 (eastern portion of Uinta Basin) in which the type of the species was 

 obtained. In a previous publication, Protelotherium was referred to 

 Achccnodon.^'^ As the result of recent careful study of the Uinta and 

 Washakie forms I am strengthened in the opinion that they should 

 be kept under one generic name. When a liberal allowance for the 

 complete premaxillary and a correction of the frontal region (See 

 PI. XXXIX, Fig. 1) in A. robustus is made, there does not appear to 



'^ Memoirs Carnegie Museum, Vol. IV, 1909, p. 145. 



