THE NAUTILUS. 43 



Lampsilis ventricosa (Barnes) 



Lymn&a obrussa Say 



Lymn&a humilis modicella Say? (two specimens) 



Oreohelix cooper i (W. G. B.) 



Pyramidula. cronkhitei anthonyi Pils. 



Succinea avara Say 



Vallonia gracilicosta, Reinh. 



Zonitoid-es arborea (Say) 



Physa gyrina Say 



Physa Integra Hald. ? 



Planorbis parvus Say 



Only a single broken example of the Oreohelix was found, 

 in the river bottom, and it may have been brought by the 

 stream from far away in the spring flood. 



Sta. 236, creek bottom about ten or twelve miles north of 

 Uva, under willows and cottonwoods. 



Vallonia- gracilicosta Reinh. 

 Vitrina alaskana Dall. 

 Zonitoid-es arborea (Say) 



Sta. 237, five miles northwest of Douglas, in a small spring 

 brook. 



Lymn&a obrussa Say 

 Physa gyrina Say 

 Planorbis parvus Say 



Sta. 238, Boxelder Creek, about 18 or 20 miles northwest 

 of Douglas. 



Ferrissia rivularis Say 



Lymn&a obrussa Say 



Physa gyrina Say 



Planorbis parvus Say 



Pyramidula cronkhitei anthonyi Pils. 



Succinea avara Say 



Vallonia gracilicosta Reinh. 



Vitrina alaskana Dall 



Zonitoides arborea (Say) 



Sta. 239, a very small reservoir formed by throwing an 

 earth dam across a dry draw to catch the storm waters for 

 stock, four miles west of Arminta. A few very rotten shells 

 of Lymncea bulimoides cockerelli Pits. & Fer. were found. 



