72 PROCEEDINGS OF THE ACADEMY OF [Feb., 



oquirrhensis, though a few approach it. 0. h. hyhrida, from its type 

 locaUty at Logan, is readily distinguished from 0. h. form gahbiana 

 from its type locaUty in the Oquirrh Mountains, but at these stations 

 we have a puzzhng mixture and variation of characters, so that the 

 determinations are made with some hesitation. The stations are 

 not far apart and in the same canyon, so they may almost be con- 

 sidered one large colony. The form at the extremes of the colony 

 so considered, stations 48 and 54, seems referable to hyhrida, a 

 considerable proportion of those from Sta. 48 being typical, others 

 varying more or less in peripheral angulation and the altitude of the 

 spire, but the spiral sculpture in those from Sta. 54 is obscure, much 

 weaker than in the typical form. Both lots have the whorls well 

 rounded from above and below to the more or less angled, but not 

 keeled, periphery. The form at Sta. 49 (next to 48) and Sta. 53 

 (next to 54), we refer to gahbiana, not typical. It is really transitional 

 from the hyhrida of 48 and 54 to the gahbiana of 51 and 52. On the 

 average the whorls are not so well rounded, the spire flatter and the 

 angulation more pronounced, though they are somewhat variable 

 in all these characters. On the whole, they seem more nearly related 

 to the form at the nearest stations, 51 and 52, than to the form at 

 the more remote stations, 48 and 54. Some examples are entirely 

 indistinguishable from material labelled utahensis from Hemphill's 

 collection. The form at stations 51 and 52, which we refer to 

 gabhiana, has a depressed spire and the whorls slope rather flatly 

 from above and below to a keeled periphery. The spiral sculpture 

 is variable, the primary spirals in some examples being nearly as 

 strong as those in typical oquirrhensis, though only indistinctly seen 

 in others. These forms are further discussed in the sections on 

 Deweyville and Oquirrh Mountains. 



Sta. 55, a small stream by the roadside, perhaps a mile and a half 

 above Morgan, below Sta. 54. 



Lymncea proxima Lea. Aplexa hypnorum (L.), 



Physa ampuUacea Gld. 



Sta. 56, pool by the roadside, about a mile above Morgan, just 

 above where the wagon road crosses the railroad. 

 Pisidium near huachucanum Pils. Lymncea humilis modicella Say. 

 Paludestrina longinqua (Gld.). Planorhis parvus Say. 



Lymncea proxima Lea. Physa ampul' acea Gld. ? 



Sterki says of the Pisidium: "P. huachucanum Pils., or near. 

 Somewhat different' from the originals; somewhat smaller (all speci- 



