WEST AMERICAN MOLLUSKS—BARTSCH. 



165 



strongly rounded, very narrowly shouldered at the summit, marked 

 by decidedly retractively curved axial lines of growth, and exceed- 

 ingly fine microscopic spiral striations. Suture strongly impressed. 

 Periphery of the last whorl well rounded. Base inflated, well 

 rounded. Aperture subcircular; posterior angle obtuse; outer lip 

 thin; inner lip very strongly curved, thick, reflected over and ap- 

 pressed to the base; parietal wall covered with a thick callus which 

 fuses with the reflected inner lip and forms a decided callosity over 

 the umbilical region. Operculum typical. 



The specimen described and figured. Cat. No. 271483, U.S.N.M., is 

 one of a large series collected at San Diego, California. It has five 

 and one-half whorls and measures — altitude, 3 mm. ; diameter, 

 1.9 mm. 



The following additional specimens have been examined : 



126645 



150953 



152188 



56442 



56398 



23727 



32380 



32381 



32382 



152191 



185364 



56453 



105431 



198579 



99294 



152313 



32372 



195336 



271493 



273714 



'271483 



130319 



191580 



199181 



32378 



148264 



32367 



56442 



271508 



32369 



198963 

 198961 

 105542 



269160 



U.S.N.M. 



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Num- 

 ber of 

 speci- 

 mens. 



21 



4 



10 



1 



15 



5 



2 



6 



2 



1 



2 



15 



4 



15 

 3 

 6 



87 



25 



13 



4 



427 



2 



1 



2 



26 



8 



2 



]0 



27 



16 



4 

 1 



Locality. 



Vancouver Island, BritiBh 

 America. 



do 



Whidby Island, Puget Sound 



Eiu-eka, California 



Oakland, California 



do 



San Pedro, California. 

 do .-■-■:-• 



San Diego, California . 

 do 



San Diego Bay, California 



Terminal Island, California... 



Alamitos Bay, California 



Catalina Island, California . . . 



California 



do 



do 



Santo Domingo, Lower Cali- 

 fornia. 



Todos Santos Bay, Lower 

 California. 



do 



do 



Manuel Lagoon, Lower Cali- 

 fornia. 



Santa Maria Bay, Lower Cali- 

 fornia. 



1 Type. 



Mossy rocks, near low 

 tide. 



Ocean beach. 



Drift. 

 Do. 



Among grass, near high 



tide. 

 Boat dredge. 



