80 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 28 



and the posterior half of Mi. The lower jaw is from the same general 

 locality as the type but is evidently not from the same individual, as 

 the upper teeth show somewhat greater wear. It is rather surprising 

 that two specimens of this rare form should show up about the same 

 time, and fortunate that they complement one another in furnishing 

 information on both the upper and lower molars. The anterior cheek 

 teeth are not known, and no other skeletal portions in the collections 

 have been recognized as pertaining to this form. 



MEASUREMENTS IN MILLIMETERS OF DENTITIONS IN SPECIMENS OF 



Poebrodon kayi 



U.S.N.M. 



No. 



20393 



Type 



Length of upper molar series, M*-M' (posterior margin of root), 



inclusive 20.2 



M\ anteroposterior diameter : transverse diameter* 6.3 : 5.3 



M*, anteroposterior diameter : transverse diameter 7.0:6.7 



M', anteroposterior diameter : transverse diameter 7.7a : 6.8a 



U.S.N.M. 



No. 



20392 



Ml, transverse diameter of talonid 4.4 



M3, anteroposterior diameter : transverse diameter of talonid 7.0a : 4.80 



M3, anteroposterior diameter : transverse diameter of trigonid 10.7 : 5.0 



a. Approximate. 



* Measurements of upper molars are taken anteroposteriorly perpendicular to anterior 

 margin and transversely across anterior portion of tooth. 



Family LEPTOMERYCIDAE Scott, 1899 

 Subfamily Leptotragulinae Zittel, 1893 



The reasons for separating the leptotragulines from Hypertraguli- 

 dae and including them tentatively with the leptomerycines in a 

 separate family have been discussed above under the Hypertragulinae. 

 Such an arrangement seems preferable to including the leptotragulids 

 in the Camelidae, as Wortman (1898), Matthew (1903, p. 224), and 

 Scott (1899) were inclined to do. 



Attention is also again directed to the conclusion that Or ornery x, 

 generally included with the leptotragulids, does not represent this 

 subfamily but belongs in a distinct family. Oromeryx is clearly related 

 to Protylopus and should not be grouped either with the hypertragulids 

 or the leptotragulids. Moreover, Poahromylus, which Peterson de- 

 scribed as a camelid, does not appear to present characters of signifi- 

 cance other than size, suggesting the Camelidae, and seems to be more 

 closely related to the leptotragulines. Its premolars, though large, 



