TRANSACTIONS OF WAGNER 



UINTA SELENODONTS 



the type o{ Merycodcsiiiiis (Princeton Museum, No. 11,225), consists of the 

 skull and an imperfectly preserved fore-foot, and the other is a block (No. 

 11,223) containing parts of two skulls, several vertebrae, the pelvis, and hind- 

 limb nearly complete. While the parts of the skull preserved in the second 

 specimen are not sufficient to put the reference of it to the present genus 

 beyond all question, yet there is little room for doubt in the matter. It 

 certainly cannot pertain to Leptotragiilus, Protyloptis, or Oromeryx, and must 

 belong to some form either identical with or very closely allied to Leptoreodon. 



The dentition is exceedingly peculiar, and seems to unite the character- 

 istics of several distinct families. The formula is : If, Cy, Pf, M-|. 



A. Upper Jaw. (Plate II., figs. 10, 11.) The incisors are small, conical, 

 pointed, and slightly recurved; they are much smaller than in Proiylopus, but 

 have a similar shape, and, as in that genus, they are separated by short inter- 

 spaces and arranged in almost the same fore-and-aft line. A longer space inter- 

 venes between i- and the canine. The canine is large, very much larger than 

 in Protylopus, and though laterally compressed, is yet quite stout and thick ; the 

 anterior border is thickened and rounded, with a deep, narrow groove running 

 down the external face ; in cross section the tooth is D-shaped, much as in the 

 oreodonts, but thinner and more compressed laterally. As the upper canine is 

 opposed by the caniniform pj, it is the posterior face that shows abrasion. 



The premolars are quite simple. The first is placed near the canine, but 

 is separated by a long interval from p-?^; it is implanted by two roots and has 

 a small, but high, thin, pointed, and trenchant crown, which in shape and 

 position resembles that of Hypertragidiis. The second premolar is like the 

 first, but is larger, especially in the fore-and-aft dimension ; it is somewhat 

 thickened transversely. The third closely resembles the second when seen 

 from the outer side, but internally there is a marked distinction, for this tooth 

 is carried upon three fangs, and in L. gracilis has a small but distinct deutero- 

 cone; in L. viarshi i\ns is " a faint internal cingular ledge." (Wortman, '98, 

 p. 96.) The fourth premolar is of the well-nigh universal selenodont pattern, 

 composed of two transversely placed crescents. It remains only to note that 

 the external wall of the tooth is quite markedly concave, with a low median 

 rib, and that the inner cingulum is prominent. 



The molars are composed of four cusps only, and Wortman was mistaken 

 in supposing that the anterior intermediate cusp was probably present, as un- 

 worn specimens clearly show. They bear considerable resemblance to those 

 oi Protylopus, and, indeed, it is a difficult task to identify scattered molar teeth 



