82 THE NAUTILUS. 



Lymnsea reflexa Say. St. Michaels, Buffalo Co., and Bellevue. 



Lymnsea caperata Say. West Point, Cuming Co., and Dewey's 

 Lake, Cherry Co. 



Lymnsea desidiosa Say. Monroe Canyon. 



Lymnsea palustris Mull. Dewey's Lake and Marsh Lake, Cherry 

 County. 



Physa anatina Lea. Lincoln ; "Washington, Cedar Co. ; Roca and 

 Platte River. 



Physa gyrina Say. "West Point, St. Michaels and South Bend. 



Physa gyrina hildrethiana Lea. Lincoln and Hat Creek Valley, 

 opposite Monroe Canyon. 



Physa gyrina oleacea Tryon. Bellevue. 



Physa heterostropha Say? Omaha. A few very young specimens 

 seem referable to this species. 



Physa ancillaria Say. Hackberry Lake, Dewey's Lake and 

 " Sink " near Dewey's Lake, Cherry Co. Fine, large specimens. 

 Those from the " Sink " are elegantly striped like Lymncea reflexa 

 zebra, a rare occurrence in this genus. 



St. Michael. A more typical example. 



Physa sayi warreniana Lea. Lincoln. 



Physa Sp. ? Dewey's Lake, Cherry Co. A single specimen re- 

 sembling P. aplectoides Sterki, but with a short, obtuse spire and 

 well-impressed suture. 



Aplexa hypnorum L. Dewey's Lake and Marsh Lake, Cherry Co. 



Planorbis trivolvis Say. Bellevue, St. Michael, Lincoln, Hack- 

 berry Lake and Dewey's Lake, Cherry Co., Omaha and South Bend. 



Planorbis h'carinatus Say. Sidney, Cheyenne Co. One example 

 is slightly transversely striate, approaching var. striatus. 



Planorbis parvus Say. Omaha and Lincoln. 



Segmentina armigera Say. Omaha. 



Ancylus shimekii Pils. Calloway. 



Ancylus rividaris Say. Deadman's Run, Lincoln. 



Ancylus tardus Say. Lincoln. 



Ancylus Sp. ? Lincoln. 



Amnicola limosa Say. Lincoln. 



Sphcerium simile Say. Lincoln. 



Sphcerium slamineum Con. Salt Creek, Lincoln. 



Sphcerium striatinum Lam. Lincoln. 



Musculium jayanum Prime. Lincoln. 



