THE NAUTILUS. 131 



state of Montana, so tliat the following list of species from the upper 

 Musselshell Vjilley, in the central part of the slate, is of interest 

 from a disirihulinnal standpoint. Tlie exact locality is Winnecock, 

 Meagher County, where the writer has dune a little collecting dur- 

 ing August of two succeeding years (1911-1912). The fresh-water 

 species were taken in the various springs and overflow pools horder- 

 ing the Musselshell River, and the terrestrial spenes occurred under 

 sticks, leaves and stones in the more moist places among the sur- 

 rounding cottonwoods. No species were taken in the swift-flowing 

 waters of the river itself, and no land forms were found at a greater 

 distance from the river than a few rods. All except Vertiyo hhi' 

 neyona, ZonitouJes nniiuscufa and Planorbis calliogiyptus were of 

 fairly frequent occurrence. The elevation of Winnecock is about 

 4000 feel about sea level. 



Vuilonia costata montana Sterki. The specimens appear to cor- 

 respond very well with Dr. Steiki's diagnosis, and specimens sent to 

 Mr. George H. (Jlapp were similarly determined by him. They are 

 possibly the same as the ^^VuUonia graciUcosta var., close to costata 

 Say," of Sqnyer's list. 



Vitrea radiatula Alder {hammonis Strom.). 



Zonitoides urborea (Say). 



Zonitoides minuscula (liinney). 



Eucontdus fulvus (Miiller). 



jigriolhuax campestris (Binney) var. The specimens are perhaps 

 to be referred to the niontmrns of IngersoU. 



Pyrnnfidula cronlhitei (Newcomb) near var. anihouyi Pilsbry. 



Succinea ovara Say. 



Siiccinea retusa Lea. 



Lymvaa palustris Miiller. 



Lymnaa caperata Say. 



Plunorhi's parvus Say. 



Planorbis caUhglyphis Vanatta. A single poor specimen is thus 

 somewhat doubtfully determined. 



Planorbis antrosus Conrad (= bicarinatus Say). 



Physa gyrina Say var. 



Aplexa hypnorum Linn 6. 



