THE NAUTILUS. 93 



Flanorbis parvus Say. Deuel, Pennington, Clap and Hard- 

 ing Counties. 



Planorbis exacuus Say. Deuel Co. near Altimont. 



Planorhis trivolvis Say. Quite common over the State. Also 

 collected in Beadle Co. in 1895 by S. F. Adams. 



Planorbis deflectus Say. Clay, Perkins, Deuel, Washington 

 and Washabaugh Counties. 



Planorbis tumidus Pfr. Perkins and Deuel Counties. 



Segmentina armigera Say. Clay and Deuel Counties. 



Segmentina christyi Dall. Dead shells were abundant at a 

 small pond in Deuel Co. in 1908. 



Ancylus parallelus Hald. Deuel Co. 



Valvata tricarinaia Say. Codington, Clay and Deuel Counties. 



Campeloma integrum Say. Clay Co. Vermilion River. One 

 sinistral. 



Somatogyrus subglobosus Say. Deuel Co. 



Somatogyrus integer Say. Deuel Co. 



Amnicola dncinnatiensis Anth. Spink Co. Turtle River. 



Amnicola limosa Say. Codington and Clay Counties. 



Amnicola emarginata Kiist. Codington and Clay Counties. 



Lampsilis luteolus Lam. Clay, Deuel, Codington and Spink 

 Counties. One "dead" specimen was found in the Little Mis- 

 souri River in Harding Co. It is doubtful if it exists there at 

 present, but may be found in the same river at higher elevation 

 and in a sandy loam formation in Montana. 



Lampsilis ventricosus Barnes. 



Lampsilis leevissimus Lea. 



Lampsilis alatus Say. 



Lampsilis parvus Barnes. Vermillion River, Clay Co. 



Lampsilis gracilis Barnes. The above five species are no doubt 

 more or less common in the Big Sioux, Vermilion and James 

 Rivers. 



Lampsilis anodontoides Lea. Clay Co. 



Lampsilis subrosti-atiis Say. Rare in Brule Creek, Union 

 County. 



Lampsilis rectus Lamk. Brule Creek, Union Co. 



Plagiola elegans Lea. Clay Co. 



Slrophitus edentidus Say. Lake Kampeska, Codington Co. 



