100 Annals of the Carnegie Museum. 



distal end of the cuboid small and displaying no sign of a fifth digit, and 

 the pes was therefore didactyl, as Marsh says. 



This type material seems to me to be an unfortunate mixture of 

 Lcptotragiihis, probably of Protoreodon, and possibly also of Oromeryx. 

 If the tooth designated by Marsh as Parameryx should after all prove 

 to be a second molar of Oromeryx it would further complicate matters, 

 as we would be forced to accept Parameryx, and relegate Oromeryx 

 to the synonj-my, inasmuch as Parameryx was, strictly speaking, first 

 mentioned by Professor Marsh in his address. "^^^ 



That the Hypertragulids of the Uinta Eocene represented by Lep- 

 totragiiliis, Leptoreodon, and Oro?neryx are three closely related genera, 

 which naturally fall into the subfamily Leptotragulina, appears to 

 admit of little or no question. But whether or not any or all of these 

 Uinta forms are directly ancestral to the forms from the American 

 Oligocene we are not yet in a position to state. All who have studied 

 them agree that they have many anatomical features in common with 

 the Oligocene genera. However, in the cases which afford the best 

 opportunities for comparison, there appear, grouped together in a single 

 form from the Uinta, characters which appear to be held in common by 

 any one of two or three dififerent genera from the Oligocene. These 

 characters of the specimens from the Uinta are collectively such 

 that the animals, which the remains represent, may be said to have 

 had a common ancestor, but it is not possible to say that they point 

 to any particular genus of the Oligocene'^- as a derivative. Future dis- 

 coveries and studies may possibly prove that all the species "of the 

 Uinta hypertragulids have individually characters which agaifl may 

 be recognized in the different Oligocene genera, and we know, for in- 

 stance, that Leptotragulus has certain features in common with Hetero- 

 meryx, Leptomeryx, and Hypertragulus. This mixture, or combination 

 of characters, in Leptotragulus which are revealed by the Oligocene 

 genera, is then, as I regard it, the expression of a relationship springing 

 from a common descent from the old Pecoran stock. Certain new 

 or more recently acquired features characteristic of the Hypertragalidce 

 of the Oligocene, express progression toward types which had their 

 origin and gradual development, as these forms were dispersed from 

 centers where the most rapid moulding and development of new char- 



^^^ Amer. Jour. Sci., Vol. XIV, 1877, p. 364. 



^2 The same may well be said of the Uinta protorcodonts, as pointed out by 

 others. 



