90 BULLETIN 171, UNITED STATES NATIONAL MUSEUM 



only outstanding difference noted is the greater size of the Maryland 

 type as compared with the Cahfornia forms. In addition, the pre- 

 molars in the lower jaw, Univ. Cahf. Pal. Coll. no. 8756, from Potter 

 Creek Cave, which the junior author examined, appear to be slightly 

 more hypsodont, and the isolation of the lingual fold in P3 is more 

 complete. 



In view of the disparity in size, it is possible that were more com- 

 plete material laiown exhibiting the skull and horn structure Eucera- 

 theiiumit) americanum would be found to represent a distinct genus. 

 On the dental structure alone, however, no important differences can 

 be cited that would serve to distinguish this form generically from 

 Euceratherium or Preptoceras. 



Our form is referred tentatively to Euceratherium, as apparently 

 the differences that separate Preptoceras from Euceratherium may not 

 be greater than could be accounted for by individual variation. No 

 important dental differences were seen between the two, although the 

 teeth in the type of Preptoceras are slightly larger than in Eucera- 

 therium. 



