540 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. [1885. 



Opalia crenatoides Cpr. 



San Diego -, not common. Also Todos Santos Bay. 



lanthina bifida Totten. 



Specimens often washed ashore at San Diego. 

 Odostotaia uuciformis Cpr. var. avellana Cpr. 



San Diego. 

 Odostomia iuflata Cpr. 



San Diego ; not rare. Also a variety (?) more slender and elevated 

 proportionally, but otherwise similar. 

 Odostomia aequisculpta Cpr. 



Abundant on the shells of Haliotia. 



[San Diego to Cape St. Lucas. D.] 

 Turbonilla torquata Gld. 



Abundant on the shells of Haliotis. 

 Turbonilla aurantia Cpr. 



San Diego. 

 Chrysallida pumila Cpr. 



[Rare. Todos Santos. D.] 

 Obeliscus variegatus Cpr. 



San Diego Bay ; dead specimen ; rare. 

 Litorina planaxis Phil. 



Abundant. 

 Litorina scutulata Gld. 



More abundant than the above in sheltered places. 

 [Also var. L. plena Gld. very large and fine. D.] 



Lacuna variegata Cpr. 



On sea-grass ; abundant in the spring. 

 Lacuna unifasciata Cpr. 



San Diego. Not common. 

 Rissoina interfossa Cpr. 



[Todos Santos. D.] 

 Isapis fenestrata Cpr. 



Specimens from among oyster shells below low water, off an old pile 

 from San Diego Bay. Also Todos Santos Bay. 

 Mesalia tenuisculpta Cpr. 



San Diego. 

 Bittium quadrifilatum Cpr. 



San Diego. 

 Bittium armillatum Cpr. 



Abundant on sponges found during the spring on muddy flats, San 

 Diego Bay, at low water ; dead ones abundant among worn shells. 

 Cerithiopsis assimilata C. B. Adams. 



San Diego. Not found alive. 

 Cerithidea sacrata Gld. 



Abundant in salt marshes and on muddy flats. 



