THE NAUTILUS. 105 



Euconulus trochijormis (Montagu) -fulvus Miill. Specimens were 

 found plentifully on old boards under the wooden floors. of the 

 sleeping tents. 



Zonitoides arborea (Say). This is the commonest snail here, as 

 in our eastern forests, and is found everywhere in large quantities- 

 Specimens from Idaho and Chicago cannot be distinguished. 



Pyramidula solitaria occidentalis (Marts.). This fine shell was 

 found only high up on the mountain sides at an elevation above 4000 

 feet. At this height they were very abundant for about 500 feet, 

 when they totally disappeared, their ecological elevation being be- 

 tween 4000 and 4500 feet. They were found in hollows in well- 

 wooded ravines at the base of rocky projections, where there was a 

 vigorous growth of shrubs, and in dell-like valleys between mountain 

 spurs. They were always found (in September) buried under leaves 

 and debris, sometimes to the depth of several inches. The color is 

 rich brown or chestnut, with two reddish bands, which are specially 

 conspicuous in the aperture. 



These shells were at first somewhat of a puzzle, for they seemed 

 to combine characteristics of both Oreohelix cooperi and Pyramidula 

 solitaria. Prof. Elrod * notes a similarity between these two species 

 near McDonald Lake, Mission Mountains, Montana. To Mr. Wm. 

 Moss, Superintendent of the Kootenai Orchards, is due the discovery 

 of these shells. We had searched diligently for nearly two weeks 

 without finding even a dead specimen, though the mountain side had 

 been ascended for a thousand feet. Upon mentioning the fact to 

 Mr. Moss, he stated that he had seen piles of big shells way up on 

 the mountains. A subsequent climb to this altitude (2000 feet above 

 the orchard) revealed the coveted Helices. 



Galba parva (Lea). This little Lymnreid was found only in a 

 small creek at McArthur. 



Physa diaphana Tryon. The Orchard, McArthur; Moravia, 

 about eight miles north of McArthur. This is the common Physa 

 and occurs in some localities in great abundance. 



Chaos in the Physid& is painfully realized when one attempts to 

 definitely place a member of this family. Diaphana was originally 

 described from California, but the species under discussion, though 

 occurring so far to the eastward of this region, conforms to the 



'Bull. University of Montana, Biological Series, No. 3, p. 112. 



