FREE INSTITUTE OF SCIENCE 



51 



UINTA SELENODONTS J 



acter of these bones, and is so uncertain that no dependence can be placed 

 upon them in attempting to decide the nature of the genus. Wortman 

 ('98, p. 104) has described a remarkable pes which he attributes to Lepto- 

 tragulus [Parameryx), but the reference is veiy problematical. 

 The single well-defined species is L. proavus S. and O. 



The Systematic Position of Leptotragulus . 



The difficulty in making a satisfactory reference of this genus lies simply 

 in our very imperfect knowledge of it, and until we have learned the character 

 of the anterior teeth and of the feet the difficulty will remain. The similarity 

 of the lower teeth to those of Protylopus is so very close, even in minor details, 

 that the genus is included in the same family as the latter, though with a 

 question, for should the caniniform tooth eventually prove to be a transformed 

 premolar, it would be necessary to remove Leptotragulus from that family. In 

 this case the connection of the main tylopodan phylum with Leptorcodon, and 

 through that genus with the oreodonts, would be made all the closer. 



In my former account of Leptotragulus ('89, p. 483) I pointed out that 

 the presence of only three inferior premolars would, if confirmed by other 

 specimens, render the known species, at least, ineligible for a place in the 

 direct line of tylopodan descent. By the discovery of Protylopus, Lepto- 

 tragulus is made to take its place as a side-branch of that stem. Among 

 the White River genera Hypertragulus seems to be the one most likely to 

 have descended from the Uinta form, which wouid serve to explain its many 

 resemblances to Poebrotherium and its intermediate position between the 

 latter and Leptomeryx. If the lower caniniform tooth of the Uinta genus 

 should prove really to be a canine, then its position, here suggested as 

 ancestral to Hypertragulus, would be much strengthened. However, until 

 much more complete material of the Uinta genus has been collected its 

 taxonomic position must remain an open question. 



Family II. LEPTOMERYCIDyE. 



Leptoreodon Wortman. 



Plate II., Figures 10-14. 



Bull. Amer. Mus. Nat. Hist., N. Y., x., p. 95. (April 9, 1898.) 

 Merycodesmus Scott, Proc. Amer. Phil. Soc, xxxvii., p. 75. (April 15, 1898.) 



The following description is founded upon two specimens, one of which, 



