64 PROCEEDINGS OF THE ACADEMY OF [Feb., 



figuring one with the spire depressed out of sight in lateral view. 

 If further material shows the Oregon form to be worthy a name, 

 it should be given a new one and not called convexior. 



Sta. 87, just within mouth of Logan Canyon, on south side. 

 Oreohelix strigosa depressa (Ckll.) very abundant, rather small, 

 nearly white, with two conspicuous, usually broad, dark brown bands, 

 which almost invariably extend to the aperture. These are the most 

 conspicuously banded snails we found during the two seasons' work, 

 except 0. peripherica form albofasciata. They were found scattered 

 for a mile up the canyon, and were quite abundant in a small rock 

 slide covered by Clematis. This station also yielded the following: 



Vitrina alaskana Dall. Thysanophora ingersolli (Bland). 



Pyramidula cronkkitei anthonyi Euconulus fulvus alaskensis VAs. 

 Pils. 



A spring choked with water-cress yielded Paludestrina longinqua 

 (Gld.). Sterki^"* doubtfully recorded Vallonia gracilicosta Reinh. 

 from Logan Canyon. 



Sta. 88, about a mile up, on the south side of next large canyon, 

 about two miles to the north from Logan Canyon. Oreohelix strigosa 

 ■depressa (Ckll.), a few alive under mountain maples in the edges of 

 rock slides, dead shells common. 



Sta. 89, between 87 and 88, along the west slope of the mountain. 

 Oreohelix haydeni hyhrida (Hemph.), dead shells scattered, but 

 especially common where limestone ledges are exposed at the mouths 

 of small ravines. About a dozen live snails were found under sage- 

 brush in rock slides, but none under Balsamorrhiza, which is usually 

 excellent cover for Oreohelix where it droops over rocks. Here the 

 plant was found in loose soil, not about the rocks. The evidence is 

 abundant that the vegetative cover has here been greatly reduced by 

 overgrazing, followed, as usual in such cases, by active erosion. The 

 €olony is likely near extinction. A few dead shells of Vitj-ina alaskana 

 Dall were found. 



Sta. 90, several steep, short ravines on the west slope of the moun- 

 tains south of Logan Canyon and south of our Sta. 42, 1915. Oreo- 

 helix haydeni hyhrida (Hemph.) found sparingly in all of these ravines. 

 This form seems to be here confined to such situations and is not 

 found in the larger canyons, which are the best places for depressa 

 and cooperi. 



I. 



1^ Proc. Acad. Nat. Sci. Phila., 1893, p. 270; Man. Conch., 2d Ser., vol. VIII, 

 p. 256. 



