NO. 1854. 



NEW WEST AMERICAN M0LLUSK8—BART8CII. 



265 



tome double, the inner fusing with the anterior portion of the outer 



hp, while posteriorly it is distinct and at a considerable distance 



from the columella and the parietal wall; the space 



between the columella, parietal wall and the inner 



peristome is bridged over by a concave band of shelly 



matter. 



The type (Cat. No. 213541, U.S.N.M.) has two and 

 a half post-nuclear whorls and measures: Length 

 1.1 nun., diameter 0.7 mm. It and another specimen, 

 entered under the same catalogue number, were taken 

 from sea moss at La Jolla, California, by Mr. F. W. 

 Kelsey, in whose collection there are nine additional 

 specimens from the same locality. Another specimen 

 (Cat. No. 32374, U.S.N.M.) comes from Monterey, 

 California, while seventeen more (Cat, No. 186026, U.S.N.M.) were 

 taken from mossy rocks at low tide at San Diego, California. 



Fig. 3.— Amphitha- 

 lamus tenuis 

 Bartsch. 



