86 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 128 



cf. primus at the Leota Ranch quarry, all appears to represent a 

 smaller, more slender toothed species than Leptotragulus medius and 

 may well represent Leptotragulus clarki. 



Genus LEPTOREODON Wortman, 1898 



Synonyms. — Merycodesmus Scott, 1898. 

 Camelomeryx Scott, 1898. 



Type. — Leptoreodon marshi Wortman, 1898. 



Discussion. — Merycodesmus and Camelomeryx were named by 

 Scott in a paper presented before the Philosophical Society in March, 

 1898, but not published until April 15, 6 days after Wortman's paper 

 that included the description of Leptoreodon. Careful comparison of 

 the materials representing these three convinces me that only one form 

 is represented. 



The principal characters defining Leptoreodon have been discussed 

 above in comparison with Leptotragulus. It has been noted that 

 Leptoreodon is characterized as distinct from Leptotragulus essen- 

 tially in the different development of the lower premolars. In these, 

 notably P3 and P4, there is only a single crest immediately posterior 

 to the apex of the protoconid, but in both these there is a distinct 

 metaconid which is joined by a spur to the principal posterior crest 

 at some position behind the protoconid. This arrangement generally 

 leaves a prominent forward- and inward-facing groove between these 

 cusps, particularly in P4, which is rather unlike Leptotragulus. More- 

 over, there is generally a well-defined cusp at the posterointernal 

 extremity of the posterior crest in the position of an entoconid in P4 

 and possibly, though not clearly observed, in P3. Also, the parastylid 

 of these two teeth is not clearly distinguished on the anterior crest 

 in Leptoreodon. In Leptomeryx the metaconid and entoconid are 

 well developed, but in P4 the metaconid is nearly opposite and joins 

 the protoconid, and the large entoconid nearly or quite joins the 

 metaconid. In P3 the metaconid is weak and takes the form of a 

 crest extending posteriorly from the protoconid. The entoconid 

 usually does not join it but unites with the principal posterior crest 

 about midway of its length. Leptomeryx, moreover, exhibits a well- 

 developed parastylid on P2 to P4. 



In the upper premolar series less of significance was observed, but 

 P* in Leptoreodon appears broader transversely and the deuterocone 

 preserves somewhat more of its identity as a cusp. In Leptotragulus 

 the deuterocone is perhaps more selenodont, and P^ and P^ exhibit 

 a better-developed tritocone. 



