1916.] NATURAL SCIENCES OF PHILADELPHIA. 333 



distance from Hemphill's camp, above irrigation canal, in a dense 

 thicket of birches and mountain maples. Forms albofasciata and 

 binneyi, showing the same intergradation as at Sta. 29, but a smaller 

 proportion strongly banded. Of 324 live ones examined, only 39 

 showed very marked bands, most of which were as heavily banded 

 as at 29. Diameter 16 to 18 mm. In the dried-up backwater from 

 the canal at this point we found 80 Lymnaea parva Lea (identified by 

 Walker), 1 Planorbis parvus Say, 7 Physa gyrina Say (?), 2 Zonitoides 

 arborea Say and 1 Vitrina alaskana Dall. 



Sta. 34, above Wheelon, in a ravine on the east side of the gorge, 

 at the south end of the railroad bridge southwest of the tunnel, only 

 a few rods within the eastern border of Box Elder County, under 

 mountain maple, scrub oak and other brush. The same forms of 

 Oreohelix as at stations 29 and 33, but the albofasciata form propor- 

 tionately more numerous than at Sta. 33, the banding varying 

 greatly in degree as elsewhere. 



It will be noted that wmerever the form albofasciata was found, 

 it was associated with the binneyi form, and that at none of the 

 albofasciata stations was the ribbing as pronounced as at stations 

 30 and 31, at which none of the typical albofasciata were found. 

 This suggests that notwithstanding the complete intergradation in 

 all the observed characters of these snails at stations 29 to 34, it 

 may become necessary to recognize two distinct subspecies. In 

 that event the name peripherica should be adopted for the multi- 

 costata form, because it better conforms to Ancey's description and 

 Ancey himself recognized the identity of these two, and did not 

 recognize their identity with any of the other named forms. Then 

 the forms from stations 29, 33, 34 and 37 may be called 0. peripherica 

 binneyi (Hemph.), with albofasciata as a color form. Living 

 specimens from these stations have been retained for breeding 

 experiments. 



Sta. 37, about five miles across the valley due west of Sta. 36, 

 a mile or so southwest of Clarkston, in a ravine in the east slope of 

 the same narrow mountain range that the river cuts through at 

 stations 29 to 34, and probably not more than three miles northwest 

 of 29, under low bushes. The binneyi and albofasciata forms, showing 

 the usual intergradations. From the topographic and biologic 

 conditions observed at a distance, it is not unlikely that this colony 

 extends with a few narrow interruptions, to a point on the river bank 

 just opposite Sta. 29. 



Sta. 36, west slope of a small, rounded, barren-looking, isolated, 



