228 EOCENE FAUN^. 



Pelycodus jarrovii Cope. 



Systematic Cntal. Vert. Eocene, New Mexico. U. S. Expl. Surv. W. of 100th Mer., 187.">, p. 13. Prololo- 

 mu» jarrovii Cope, Ann. Rep. U. S. Geog. & Geol. Expl. Surv. \V. 100th Mer., in report of Chief 

 of Engineers, 1874, p. 1"26. Tomitherium jarrovii, Rep. Expl. Survey W. of 100th Mer., G. M. 

 Wheeler, iv, pt. ii, p. 137, 1877. 



Part of a mandibular ramus supporting the last two true molars from 

 the "Wind River beds has the dimensions of this species, and is probably to 

 be referred to it 



Pelycodus TUTUh Cope. 



Bulletin U. S. Geol. Surv. Terrs. 16^1, p. 187. Tomitherium tulum Cope, Report Expl. Snrv. W. of 100th 

 Mer., under Capt. G. M. Wheeler, iv, pt. ii, p. 141. 



Plate XXVo, figs. 1-3. 



Jaws of six individuals of this species from the "Wind River beds are 

 contained in my collection. Two of these include both rami of the mandi- 

 ble, and two others a greater or less part of the superior dentition. 



In one of the latter most of the right premaxillary and left maxillary 

 bones are preserved. The former is light, and supports only two teeth, and 

 although the apex is broken away I do not believe in the existence of a 

 third incisor. My belief is partly based on the wide spaces which separate 

 the posterior incisor from both the anterior incisor and from the maxillary 

 suture. The crown of this tooth, the only one preserved, is small, and is 

 directed obliquely forwards ; its posterior face is concave, and the cutting 

 edge is thin. The fourth superior premolar and all the true molars have 

 anterior and posterior basal cingula, which on the last two true molars 

 extend round the inner base of the crown. It extends round the external 

 base of the four molar.s mentioned. The exterior border of the last molar 



