BUPFALO SOCIETY OF NATURAL SCIENCES 115 



E 2421 Complete right lower dental plate of a mature individual 

 (PL 38, fig. 6). 



E 2425 Three beaks of lower dental plates, about as large as the type 

 specimen, 



E 2426 A left lower dental plate somewhat smaller than the type 

 (PL 38, fig. 2). It is one of the most perfect specimens 

 found, and shows well the characters of the species. 

 Total length, 86 mm. (including 3 mm. allowed for mis- 

 ing posterior extremity); depth at about middle of 

 element, 21 mm. 



E 2427 An incomplete right lower dental plate of an older specimen 

 than the preceding. That it is older is shown by the 

 blunt, worn-down condition of the cutting edge behind 

 the beak, which has the appearance of a tritor rather 

 than a cutting edge. Only the front region of the 

 tritor proper is preserved. 



E 2429 An imperfect left lower dental plate on limestone, shown in 

 inner view. The beak as well as the greater portion of the 

 functional margin are lacking, so that it is not absolutely 

 certain that the specimen belongs to this species; it 

 resembles this species, however, more than any other. 



E 2434 Fragmentary dental plate showing the greater portion of 

 the pre-tritoral cutting edge and the front half of the 

 tritor of a rather young specimen. 



E 2437 Well-preserved beak of a large lower dental plate. 



The following specimens perhaps also belong to Ptycodus howlandi, 

 but this cannot be asserted positively. They are also from the Cono- 

 dont Bed at Eighteen Mile Creek. 



E 2456 Three anterior extremities of upper dental plates of dif- 

 ferent sizes. 



