Genus Macoma, Leach.
Macoma indentata, Cpr. n. s. State Collection, No. 365.
M. t. “M. sectæ” simili; sed postice valde rostratâ, sinu inter plicam et regionem ventralem valde expansam indentato.
Long. 2·20, lat. 1·40, alt. 0·56.
Hab. San Pedro, (young, living, Palmer;) large dead valves, Cooper.
Differs from M. umbonella, Lam., in its secta-like post-ligamental wing. This being rubbed off in the large dead valves, the shell has the aspect of a very distinct species.
Genus Œdalina, Cpr.
Œdalia, Cpr., Brit. Ass. Rep., 1864. (pre-occup.)
Subgenus Cooperella, Cpr.
Œdalina; cartilagine fossâ semi-internâ, ligamento externo contiguâ, sitâ; dentibus cardinalibus laminatis, haud bifidis, sen uno bifido.
Dedicated to the memory of Judge Cooper, of Hoboken, N.J., author of the Report on the Mollusca of the Pacific Railway Expeditions.