190 SHELLS OF SAN PEDRO BAY—WILLIAMSON. 
Cardium quadragenarium Conr. 
Found at very low tide in the spring. Deep water examples are 
sometimes 64 inches from the umbo to the basal margin of the valves. 
Also found fossil at Dead Man’s Island. 
Subgenus HEMICARDIUM Cuvier. 
Cardium (Hemicardium) biangulatum Sby. 
Fresh valves, and two or three complete shells collected at Catalina. 
“Alive in twenty to thirty fathoms near Catalina Island.” (J. G. ©.) 
Subgenus LIocARDIUM (Sw.) Morch. 
Cardium (Liocardium) elatum Sby. 
One or two juvenile valves reported. 
Cardium (Liocardium) substriatum Conr. 
Plentiful at times. 
Family CARDITID4. 
Genus VENERICARDIA Lamarck. 
Venericardia ventricosa Gld. 
Two shells; San Pedro Bay. Arnold. Dredged off Catalina Island 
in 30 fathoms. 
Genus LAZARIA Gray. 
Lazaria subquadrata Cpr. 
Single valves occasionally found. Complete shells very rare. 
Family LUCINIDA. 
Genus LUCINA Brug. 
Lucina californica Conr. 
A few found alive at the Points. 
Lucina ceequizonata Stearns. - 
Dredged in 276 fathoms off the Santa Barbara Islands by the U.S. 
Fish Commission. 
Lucina Nuttallii Conr. 
Washed ashore in the bay. 
Family DIPLODONTID A. 
Genus DIPLODONTA Bronn. 
Diplodonta orbella Gld. 
Living examples are very rare. 
