University of Michigan 



mens. lUit. taken as a ^vll()le, 1 think that they are all referable 

 to one species. 



11. Planurbis triz-ohis Saw — Abundant in ponds in the 

 bed of and along- the Huml)i)ldt River, and in dry pond, west 

 of tunnel, Moleen Canyon. 



12. Planorbis parzits Say. — Ponds along- Susan Creek: 

 jNIaggie Creek; oxbow in ^^laggie Canyon; oxbow and marsh 

 ponds 1)\- the IfumlDoldt River; ]t)nd l)y railroad track and 

 spring- in Cortcz foot-hills. 



13. Fluminicola nevadensis n. sp. 



Shell minute, narrowly umbilicated, globose, rather thick 

 for so small a species, pale greenish horn-color, smooth, with 

 very fine, regular lines of growth ; whorls y/2 ; spire short, 

 apical whorl small and somewhat elevat- 

 ed, giving a mamilliform appearance 

 to the spire, the succeeding whorls are 

 low and flatly rounded, not constricted 

 by the suture, which is well impressed 

 and becomes deeper and wider towards 

 the aperture ; l)ody-whorl large, glo- 

 bosely rounded anrl in its last half descends rapidly; aperture 

 large, decidedly angled above and regularly rounded below, 

 entirely solute or barely touching the body whorl, thickened 

 throughout by a callous deposit, \vbich is heavier and some- 

 what flattened on the columellar margin ; inner lip separated 

 from the umbilical region by a distinct groove. 



Alt. 2, diam. 2 mm. 



A spring in the Cortez foot-hills, Humboldt Valley, Klko 

 County, Nevada. Cotypes in the collections of the University 

 of the Michigan, the rhiladcljihia Academy of Natural Sciences 

 and Brvant Walker. 



