THE NAUTILUS. 95 



E. hillebrandi yosemitensis, new subspecies. Rock slides near 

 Vernal Falls. 



Darker in color than typical hillebrandi; more depressed in 

 form, and with a much wider umbilicus. The three specimens 

 found measure as follows : 



Altitude 11 diameter 26 mm. 

 10.2 " 23.5 " 

 10 " 25 " 



E. mormonum cola Pils. Near Spring on Lincoln Highway. 



Polygyra columbiana Lea. Near Spring on Lincoln Highway. 



Polygyra loricata Gld. New variety? on Lincoln Highway. 



Polygyra loricata Gld. (typical). Under sticks on edge of 

 Wawona Forest. 



Succinea stretchiana Bid. Wawona meadow. 



Vertigo ovata Say. Wawona meadow. 



Vertigo modesta castanea Sterki. Wawona meadow. 



Striatura milium meridionalis Pils. and Ferriss. Edge of Wa- 

 wona Forest. 



Zonitoides arbor ea Say. Meadow south of Wawona, also Big 

 Oak Flat Road. 



Pyramidula cronkhitei Newc. Edge of Wawona Forest ; also 

 Big Oak Flat Road. 



Euconulus fulvus alaskensis Pils. Edge of Wawona Forest. 



Vitrea chersinella Dall. Meadow south of Wawona. 



Vitrina alaskana Dall. Big Oak Flat Road and Moss near 

 Vernal Falls. 



Physa diaphana Tryon. Stream at "Coarse Gold." 



Planorbis umbilicatellus Ckll. Big Oak Flat Road. 



Goniobasis nigrina Lea. Spring on Placerville Road. 



Pisidium abditum Hald. Big Oak Flat Road. 



Pisidium occidental Newc. Big Oak Flat Road. 



Sphaerium occidentals Prime. Big Oak Flat Road. 



NOTES. 



PLANORBIS DILATATUS AND P. SAMPSONI. Besides its greater 

 size, P. sampsoni differs from typical dilatatus by its very much 

 more widely open umbilicus. The two species seem to be fairly 

 distinct. Various forms which in collections are often referred 



