

BULLETIN 



OF THE 



esses: IISrSTITTJTE. 



Vol. 20. Salem : Apr., Mat, June, 1888. Nos. 4-6. 



AN ANNOTATED 

 CATALOGUE OF THE MOLLUSCA OF IOWA. 



BY CHARLES R. KEYES. 



The following catalogue of the mollusca of Iowa is based 

 chiefly upon collections personally made in various portions 

 of the state, supplemented by liberal accessions received 

 inrough exchange. With three or four exceptions, which 

 have been duly credited, only such species have been here 

 introduced as have passed under personal examination ; and 

 although there are undoubtedly some species occurring 

 within the limits of the state, but which have not as yet 

 been noted, it is presumed that the list will present a rea- 

 sonably complete resume of the regional observations upon 

 this faunal group. There are here enumerated one hun- 

 dred and fifty-one species, distributed among forty-four gen- 

 era and sixteen families ; while there are thirty-two species 

 recorded from the loss of the state. 



No attempt has been made to deal with the numerous 

 and complex questions of synonymy ; not, however, for 

 reason of any inappreciation orunder-estimation of their full 



ESSEX INST. BULLETIN, VOL. XX 6 (CI) 



