§4 Kansas universitV quarterlV. 



mens taken from the Wabaunsee formation, in southwestern 

 Shawnee county, that I am unable to distinguish from P. haivni. 

 Shells also occur in the stone upon which the Kansas river dam is 

 built at Lawrence, so similar to the type of P. hawni that I think 

 that they are certainly the same species. 



There is an interesting specimen figured on plate XIX, figs 2 and 

 2a, from Grand Summit, which is large, very spinous, and has had 

 the right valve attached. It differs in these respects from P. hawni, 

 but not sufficiently, perhaps, to be distinguished from it. The 

 beak is crushed, but appears broad. 



That the Turner form, and probably P. hawni also, are distinct 

 from P. spelimcaria is shown by the location of the retractor im- 

 pressions immediately behind the byssal groove instead of on the 

 ear above it as represented by King (loc. cit.). 



Upper Coal Measures; Turner, Wyandotte count}', Kansas. 

 Also Clements, Topeka, Lawrence, Kansas. 



