1917.] NATURAL SCIENCES OF PHILADELPHIA. 65 



Sta. 42, where in 1915 we collected 0. h. hybrida, jaelded in 1916 

 a single example of Thysanophora ingersolli (Bland), one Euconulus 

 fulvus alaskensis Pils., and three Vitrina alaskana Dall. 



Sta. 91, Providence Canyon, southeast of Providence and about 

 four miles from Logan. OreoheJix strigosa depressa (Ckll.) and 

 0. cooperi (W. G. B.), both rather small, dead shells plentiful, a few 

 live examples found under mountain maples and various shrubs in 

 rock slides. 



Sta. 92, a small stream choked with water-cress, a mile south of 

 Logan, yielded Succinea rusticana Gld., Lymncea proxima Lea and 

 Physa ampidlacea Gld. 



Baker, in his Lymnseidae of North America, records L. proxima 

 Lea and L. stagnaUs wasatchensis Hemph. from "near Logan." 



Clarkston, Utah. 



Sta. 57, Newton town reservoir, about half way between Trenton 

 and Clarkston: 



MuscuUum sp. Planorhis trivolvis hornii Tryon. 



Muscidium rykholti Normand. Planorhis exacuous Saj". 



Succinea avara Say. Plajiorhis parvus Say. 



Lymncea proxima Lea. Physa ampullacea Gould. 



Planorhis trivolvis hornii (so identified by Pilsbry) here varies from 

 19 mm. to 24 mm. in diameter. Our former record of P. trivolvis 

 from Cache Junction should be referred to this form. IngersolP^ 

 recorded hornii from Utah. 



Sta. 58, mountainside due west of the southern portion of Clarkston, 

 half a mile south of Sta. 3, 1915. Oreohelix rugosa (Hemph.) abun- 

 dant and very robust, under Balsamorrhiza sagittata and small 

 bushes, around limestone ledges. In places the ground is almost 

 white with bleached shells, and we obtained a thousand live ones 

 in a short time. In our former report we suggested (p. 334) the 

 possibility that 0. hendersoni dakani Hend. might be a synonym of 

 rugosa, a suspicion then shared bj^ Pilsbry.^'' We have since visited 

 the type locality of dakani at Newcastle, Colorado, and obtained a 

 large quantity of live specimens. Dr. Pilsbry has examined the 

 anatomy of both forms, and reports that they are distinct, the 

 anatomy of dakani proving its relationship to hendersoni, as was 



15 8th Ann. Rept. (Havden's), U. S. Geol and Geog. Surv. Terr., for 1874, 

 p. 404. 



i« Proc. Acad. Nat. Sci. Phila., LXVIII, 353, 1916. 

 5 



