50 THE NAUTILUS. 



Type Locality: 7,550 feet altitude, cienaga near Bluff Lake, 

 San Bernardino Mountains, California; under sticks and logs at 

 edge of forest; Nina G. Spaulding, G. E. Dole and S. S. Berry, 

 August, 1910; 59 specimens in this and neighboring cienagas. 



Also taken at 7,200 feet altitude, west slope of Falls Creek 

 Canyon, near the narrows about one mile above Dobbs Cabin, 

 Dollar Pass Trail, San Bernardino Mountains, California; under 

 small sticks and pine cones on springy slope; G. E. Dole and 

 S. S. Berry, Sept. 29, 1918; 32 specimens. 



Remarks : This very puzzling little mollusk is one of the most 

 beautiful of American Vertigos. It is very close to V. modesta 

 parietalis and may also be described as an albinistic race of that 

 subspecies, but it is a protean form and some shells are equally 

 close to V. modesta modesta or even to V. m. castanea. That it 

 is more than a mere ' ' albino ' ' of the recognized type is strongly 

 evidenced by its occurrence in such abundance and at scattered 

 localities, as also by the fact that its distribution is by no means 

 coincident with that of any of the other forms mentioned. 

 Nor, although usually associated, do the white or brown shells 

 occur in any apparent regular ratio. At the second locality 

 above cited diligent outlook yielded but three specimens of the 

 brown parietalis. It is evidently a comparatively recent offshoot 

 from the parent stock, but the field evidence is that it already 

 is a race with its peculiar characters heritable to a marked 

 degree. 



It seems rather remarkable that such features as the color, 

 shell texture, and similar characters in this form should exhibit 

 such constancy as compared with the variability shown in the 

 development of the lamellae. In 39 specimens of the type lot 

 now before me, 1 has only 2 teeth (columellar and parietal), 

 15 have 3 teeth (columellar, parietal, and lower palatal), 9 

 have 4 teeth (an upper palatal usually the one added), and 14 

 have a full set of 5 teeth. No mature specimens with fewer 

 than 2 nor more than 5 teeth have been noted. This variation 

 in a single well-defined colony ^its members having, as shown 

 by the other characters noted, an undoubtedly close phylo- 

 genetic relationship with one another) throws a valuable bit of 

 light on the difficulty of attempting the separation of the var- 



