72 AN ANNOTATED CATALOGUE 



Segmentina armigera Say. Hardin and Scott coun- 

 ties : rather common. 



Ancylus diaphanus Hald. Eastern Iowa generally : 

 common. 



Ancylus tardus Say. Dallas county. Both species are 

 found attached to stones or shells of Uhiones in ponds or 

 streams. 



Family VALVATID^. 



Vdlvata tricarinata Say. Abundant in ponds, through- 

 out the state. 



Vdlvata bicarinata Lea. This form has been collected 

 at Iowa City and Spirit Lake and doubtless occurs in other 

 localities in the state. A large series shows a complete 

 gradation into V. tricarinata and indeed may be regarded 

 as synonymous. 



Family VIVIPARID^E. 



Vivipara intertexta Say. Common in the ponds and 

 bayous adjacent to the Mississippi river, but has not as 

 yet been found in the interior of the state. This species 

 ranges from Louisiana north to White Bear Lake, Minne- 

 sota, where it is reported by Mr. Grant as very common. 



Vivipara contectoides W. G. B. This species has been 

 collected in the streams of eastern Iowa, but does not ap~ 

 pear to be common. 



Campeloma subsolidum Anthony. Davenport, Burling- 

 ton, Fort Dodge and elsewhere : abundant. In the Missis- 

 sippi river near Clinton very large specimens have been 

 obtained, many of them exceeding in size and weight any 

 G. ponderosum examined. The variety C. rufum Hald. 

 occurs abundantly in the Cedar river. . 



Campeloma decisum Say. Abundant ; appears to gra- 

 date into C. subsolidum. 



