122 THE NAUTILUS. 



Helix var. sodalis Hemphill. 



Shell umbilicated, very variable in size, white (faded), globosely 

 depressed ; whorls 5, the last flatly convex above and beneath, 

 smooth, under a good pocket lens appearing very minutely granu- 

 lated, falling slightly at the aperture ; spire a little elevated, obtusely 

 pointed ; sutures distinct and moderately impressed ; peristome 

 roundly thickened and reflected, its terminations approached and 

 joined by a thin callus, the basal one crowding the umbilicus; aper- 

 ture subcircular, about as broad as high ; umbilicus quite variable in 

 width, showing a portion of the penultimate whorl in some of the 

 specimens. Subfossil. 



Diam. 14, alt. 8 mm.; diam. 12, alt. 6 mm.; diam. 10, alt. 5 mm.: 

 diam. 8^, alt. 4 mm.; diam. 7, alt. 4 mm. 



Habitat: San Nicolas Island, California. 



If this interesting little shell was found in Colorado, New Mexico, 

 or along the eastern line of Arizona, it would very probably be called 

 an Ashmunella ; if it had been collected in the Ohio Valley it cer- 

 tainly would be called a Polygyra; but as it is found away out here 

 on the western limits of the continent, conchologists will be highly 

 delighted to call it Epiphragmopliora (Micrarionta) rujicincta sodalis 

 Hemph. Sometimes there is certainly a great deal (of length) in a 

 name. 



Besides the extreme variations in siz^, as shown by the measure- 

 ments, the larger forms show about the same extremes in the width 

 of the umbilicus. In the living state it must have been of about the 

 same color as H. rujicincta Newc, as a few specimens retain the 

 rufus-colored lip and a very faint trace of a peripheral revolving band. 



At my request, Dr. Dall compared a series of this shell with his 

 types of H. guadalupiana, and has kindly sent me the following 

 notes on the differences of the two forms: 



" The fossil helices are interesting. They are nearly related to 

 the recent catalince, and yet not quite the same. The large speci- 

 mens of No. 3 from San Nicolas are nearest, but have a different 

 shaped mouth, are more rounded at the periphery and rather more 

 elevated. The small form of No. 3 seems to be the same as your 

 No. 2, which are labeled guadalupiana var. sodalis. No. 1 is very 

 near guadalupiana Dall, but more solid, more rounded and with the 

 upper and lower lips on the body further apart than in the guada- 

 lupiana proper." " I regard Gabbi as distinct, as the umbilicus is 



