FREE INSTITUTE OF SCIENCE 



UINTA SELENODONTS 



minor details of structure. At all events, we may feel confident that in the 

 group of Uinta selenodonts represented by Camelomeryx and Leptoreodon we 

 shall find the forms which later diverged into the lines terminated by Lepto- 

 mcryx and Protoceras. Further, this group is unmistakably related to the 

 main tylopodan stem. Camelomeryx and Leptoreodon are already, it is true, 

 quite distinctly separated from Protylopus, but the difference lies almost entirely 

 in the anterior region of the skull and in the character of the incisors and 

 canines. The remainder of the skull and dentition are of the same type of 

 structure, as are also the limbs and feet, only in Protylopiis the elongation of the 

 manus and pes and the reduction of the lateral digits have been carried one 

 stage farther. This near alliance greatly strengthens the conclusion already 

 reached that the White River selenodonts, such as Protoceras, Leptomeryx, and 

 Hypertragidns, are derivatives of the tylopodan stem. The latter is in some 

 sense intermediate between Leptomeryx and the main tylopodan line, for in it 

 the canines have retained or reacquired their original form and function. 

 Hypertragubis, therefore, cannot have been derived from Camelomeryx or 

 Leptoreodon, but its very close resemblance in nearly all other respects to 

 Leptomeryx shows that its Uinta predecessor must have been very much like 

 those genera, except in the character of the incisors and canines. In the 

 White River it runs a course closely parallel to that of Leptomeryx, though 

 keeping an even more markedly tylopodan physiognomy, which makes it look 

 like a miniature Poebrotherinm, save for the long and slender canines. 



(?) Oromeryx Marsh. 

 Oromeryx Marsh, Amer. Journ. Sci., 3d Ser., xiv., p. 364 {iiomen nitduni). 

 Oromeryx Ma.rsh, Ibid., xlviii., p. 269. 



This genus may be distinguished from the preceding ones, Leptotragulus, 

 Leptoreodon, and Camelomeryx, by the absence of diastemata in the dentition, 

 and from Protyloptts by the much less advanced reduction of the lateral digits 

 in both manus and pes, and by the shape of the upper molars, in which the 

 anterior half of the crown decidedly exceeds the posterior half in breadth, 

 giving a curiously asymmetrical shape, which is most marked in m^ ; the 

 external median buttress is much more prominent than in Protylopus. Y^ is 

 inserted by two fangs only. In the absence of information concerning the 

 canine teeth it is uncertain whether Oromeryx should be referred to the 

 present family or the preceding one, and for the same reason we cannot 

 definitely point out the White River successor of the genus. In a general 



