JOHN RlTCHIF, - T R 

 BOX 2/2., BOSTO::, MAS:. 



Reprint from 



Proceedings Davenport Academy of Natural Sciences, 

 Volume V. 



3. 



ON CERTAIN RECENT, QUATERNARY, 

 AND NEW 



FRESH-WATER MOLLUSCA 



BY R. ELLSWORTH CALL. 



Read before the Davenport Academy of Natural Sciences, February 26th, iSSb. 



THE area which has contributed most of these forms is little known 

 conchologically. All the knowledge gathered concerning its molluscan 

 fauna is fragmentary, and, for the most part, scattered through many 

 publications, rendering a collation of their information an imperative 

 need. Such a collation has been for some time in progress, and the 

 present writer hopes soon to present a summary of the results. 



Of the six species herein described, four have hitherto been charac- 

 terized by me, two of which were, in deference to authority, given 

 only varietal rank. It is now proposed to recognize the varietal names 

 as of specific value, and to republish the original descriptions as ap- 

 plicable to the specific name. This disposition is made in the light of 

 continued and careful study of these forms in conjunction with well- 

 preserved specimens of the species of which they were formerly re- 

 garded as varieties. 



[PROG. D. A. N. 8., VOL. V.] 1 [April 15, 1886.] 



APR 26 1883 



