128 _ R. S. Lull — New Tertiary Artiodactyls. 



evolution would be demonstrably more advanced, as it is in the 

 referred specimen from the same level and locality, the middle 

 Miocene, Pawnee Creek beds of Colorado." 



B. wellsi Matthew 13 , considerably larger than B. gem- 

 mifer, occurs in the upper Miocene of the Republican and 

 Little White River valleys, the type being a lower jaw 

 from the Loup Fork beds near the Rosebud Agency, South 

 Dakota. B. wellsi differs from B. gemmifer in that the 

 premolars are relatively smaller and simpler in the 

 former ; the molars are very similar, and the jaw shorter 

 and heavier in general outline. The molars are larger 

 and somewhat longer-crowned than in either B. primus 

 or B. olcotti. 



In 1890 Professor Scott 14 described a species which he 

 refers to Blastomeryx but without specific designation. 

 The horizon he calls Loup Fork, and it is at least upper 

 Miocene and probably lower Pliocene. The main dis- 

 tinctions as given by Matthew in the later paper are the 

 more advanced skull and skeletal structure than in B. 

 primus, and the much larger size, with a small or rudi- 

 mentary antler ; the orbits are far more prominent, and 

 the ulnar shaft is reduced to " a mere thread of bone ' ' ; 

 the lateral digits are much more reduced and the shafts 

 of the lateral metacarpals incomplete. Matthew goes on 

 to say : 



"This can not well be congeneric with the lower Miocene 

 species, whether or not it be regarded as derived from them. If 

 we do so regard it, B. gemmifer would probably represent an 

 intermediate stage, as is indicated, in fact, by the little we know 

 of it. In view of the near agreement in size and other characters 

 between B. gemmifer and the lower Miocene species, it seems pre- 

 ferable to place the latter in Blastomeryx, and regard the species 

 described by Scott as referable to a more advanced genus, with 

 rudimentary antlers and with the lateral digits of the fore foot 

 incomplete. It seems inadvisable to name the upper Miocene 

 [Scott] genus until we know something more definite of its 

 dentition and skull characters and its distinctions, if any, from 

 Mazama." 



Four other species have been described: Blastomeryx 

 antilopimis Scott, B. borealis Cope, Palceomeryx ameri- 

 canus and P. madisonius Douglass. These, as Matthew 



13 Bull. Amer. Mus. Nat. Hist., vol. 20, p. 124, fig. 17, 1904. 



14 Bull. Mus. Comp. Zool., vol. 20, p. 76. 



