djgersoll.] ZOOLOGY PHYSIDiE. 401 



erosion, " which is extremely liable to happen to shells living in water 

 charged with alkaline salts other than lime." Yet quite as small and 

 black were the examples from the cold, clear, abundant springs near 

 Saguache, where there was seemingly nothing whatever to stunt their 

 growth. 



Physa Wolflana, Lea. 



In the Proceedings of the Philadelphia Academy for 1869, Mr. Isaac 

 Lea described a species of Physa from "the Hot Sulphur Springs, Colo- 

 rado," collected by Prof. J. W. Powell, which he named Physa Wo Ifiana. 

 Inasmuch as my shells came from the exact and very limited station and 

 locality (vide Observations, XIII, 67 ; PI. xxi, fig. 20) as his types, I 

 suppose I must have it; but as I cannot separate to my satisfaction 

 those which resemble that shell as described and figured, from those 

 which do not resemble it, I have remanded all to the foregoing species. 



Physa Lordi, Baird. — British Columbia (Lord), replacing P. hetero- 

 stropha on the higher ground toward the Rocky Mountains ; east of Fort 

 Colville, Washington Territory (Northwestern Boundary Survey). It is 

 not unlikely that P. ClarJcei and the two following species will prove 

 identical with this, differing only in size and color. Here, as in Limnea, 

 the shell is subject to such variation that it is precarious to predicate 

 specific rank upon the shell alone, particularly it' the specimens be few 

 and localities isolated. 



Physa ampullacea, Gould. — Oregon and "Washington Territory (Cooper)', 

 Rhett's Lake, California, and Upper Klamath Lake, Oregon (Newberry). 



Physa ancillaria, Say. — Ruby Valley, Nevada (Simpson). 



Physa gyrina, Say. — Carson, Nevada (Wheatley); Nevada (Simpson). 

 Missouri River. 



Physa humerosa, Gould. — Colorado Desert, Pecos River (Blalce). 



Physa Grosvenorii, Lea. — Dayton, Nevada ( Wheatley). 



Physa parva, Lea. — Little Valley, Nevada ( Wheatley). 



Physa Hawnii, Lea. — White Pine, Nevada (Hemphill). 



Physa Saffordii, Lea. — Fort Hall, Idaho, and Snake River Valley, 

 Utah (Beid); Nevada and Eastern Idaho (Hemphill). 



Physa virgata. — Gila River ( Gould). Southern California. 



Physa propinqua, Tryou. — White Pine, Nevada (Hemphill); Jordan 

 Creek, southwest Idaho (Gabb). 



Physa occidentalis, Try on. — Fort Colville, Washington Territory (Horn)', 

 Warners Valley, Oregon (Gabb) ; Truckee, Nevada (Carlton). 



Physa Blandii, Tryou. — Truckee, Nevada (Carlton). 



Physa malleata, Try on. — Hell-Gate River, Montana, and Fandango 

 Valley, a part of Goose Lake Valley, Oregon (Gabb). 



Physa Nuttallii, Lea. — Lewis River, Idaho (Nuttall). 



Physa Cooperi, Tryon. 



Between the Animas and La Plata 5 specimens. 



Also recorded from a spring in Crane Lake Valley, northeast Cal- 

 ifornia (Gabb). I do not feel quite sure of this determination, because 

 of the immaturity of the specimens, and the fact that I do not have 

 access to types ; nor do I altogether trust in the validity of the species. 



Bulinus hypnorum, Linn^us. 



Camp 9-10 : Grand River Valley 50 specimens. 



Bear River (Barber) 5 specimens. 



26 h 



