258 BULLETIN 16 9, UNITED STATES NATIONAL MUSEUM 



outlined the evidence in more detail. (He is discussing Mixoclaenus, 

 which now proves to be Coriphagus.) The only oxyclaenid character 

 given is "upper molars resembling those of Chriacus", but he adds 

 that they are wider transversely, more triangular, external angles 

 more prominent,^" hypocone less so, and M^ much reduced and more 

 transverse. With these, and other modifications, the resemblance to 

 Chriacus is really quite attenuated. Matthew notes that the rounded 

 condyle and other characters of the jaw and the small premolariform 

 canine are not oxyclaenid but do not approach condylarths or in- 

 sectivores. I add that they do, almost to identity, approach the 

 Anisonchinae. Matthew also notes, but rejects as inconclusive, some 

 resemblance to Didelphodus, leptictids, and Palaeosinopa in the molars, 

 but adds that the premolars suggest the Mioclaeninae but are more 

 like the Anisonchinae. 



This genus has, in fact, all the diagnostic characters of the Anison- 

 chinae and nothing that decisively indicates pertinence to any other 

 group. The upper and lower premolars are of fully anisonchine type 

 and are especially suggestive of Conacodon cophater.^^ They differ 

 in such details, well within the morphological range of the Anison- 

 chinae generally, as the incipient development of a protocone on P^ 

 and the less transverse P*. This last tooth is intermediate between 

 the "round premolar cusp" type (Hemithlaeus and Conacodon) and 

 the "flat premolar cusp" type {Haploconus and Anisonchus), adding 

 to the evidence already given by Matthew that these are not, as 

 Osborn and Earle thought, major phyletic divisions of the Anison- 

 chinae. The lower premolars still more closely resemble those of 

 Conacodon cophater, the only definite differences being that they are 

 shghtly less inflated and have the anterior basal cuspule a little smaller 

 (but larger than in Conacodon entoconus). Matthew (Pale. Mem.) 

 mentions the heavy and pecuHar wear on these teeth in Coriphagus 

 {^^ Mixoclaenus^'), truncating them obhquely. This wear occurs in all 

 Anisonchinae and is almost diagnostic of the group. 



The molars are on the whole more primitive or generalized than 

 those of other anisonchines, which is what induced Matthew to refer 

 the genus to the Oxyclaenidae. Yet they have the basic anisonchine 

 characters. The upper molars markedly resemble those of Anison- 

 chus gillianus and Conacodon cophater, apparently the most primitive 

 in this respect among other anisonchines. From the former they 

 differ chiefly in the less rounded outer contour, shorter internal slope, 

 and development of the hypocone on a cingulum around the protocone. 

 The first and last of these characters are resemblances to Conacodon 

 cophater in which, however, the internal slope is also long and the hypo- 

 cone is more internal, with respect to the protocone, than in Cori- 



"> This does not seem to me to be quite certain. • 



" Conacodon entoccnus differs greatly from tiie smaller species and might almost be distinguished from it 

 generically. 



