152 SHELLS OF LOWER CALIFORNIA— STEARNS. 



it as a different species. Adults measure from .97 inch to 1.53 inches 

 long, by .80 inch to 1.25 inches high, respectively. Though a strongly 

 characterized species, several individuals are requisite to properly rep- 

 resent it. The National collection contains a beautiful variety of the 

 above (No. 03567, U. S. N. M.) fi'om Nicaragua, in which the rounded 

 concentric ridges are quite regular, and extend over the entire surface 

 of the valves to the ventral edge. 



VENUS (ANOMALOCAKDIA) SUBIMBRICATA, Sowpvl>y. 



One perfect exam]de, several valves. Santa Margarita Islaiul, Alha- 

 tross. 



VENUS (ANOMALOCARDIA) KELLETTII, Hinds. 



Numerous examples. 



Mulege Bay {No. 41017, U. S. N. M.), one junior, less than half an inch 

 (transverse) length; Guaymas (No. 23507, U. S. N. M.), Dr. Edward 

 Palmer; also numerous valves from the latter place (No. 103280, U. S. 

 N. M.). 



VENUS (CHIONE) UNDATELLA, Sower by. 



A single example. Tres Marias (No. 03005, U. S. N. M.). 



A single specimen of this beautiful species, distinguished by its fine, 

 closely approximating concentric costa? crossing rather broad, flat or 

 slightly rounded radiating ribs, u>ore or less marked with light brown, 

 in zigzag waves, and spotted or blotched on the surface of the valves. 

 Lunule rounded cordate and dark brown. Ligamental area deeply 

 excavated and marked with brown bars on tlie left valve. Hinge line 

 very heavy. Muscular and pallia! scars strongly impressed. Coh)r 

 inside, light orange and purple. 



The various forms of this genus are so x)i"ofusely abundant on the 

 West coast, and exhibit so much variation through the influence of 

 station, character of the sea bed, etc., that no doubt too many species 

 have been made. The West American group requires careful revision. 



VENUS (CHIONE) FLUCTIFRAGA, Sower by. 



Two exami^les. 



San Juanico (No. 74204, U. S. N. M.); Scammon's lagoon; Colorado 

 Eiver, Fort Yuma (No. 30409, U. S. N. M.) ; Guaymas (No. 23595, U. S. 

 N. M.), Dr. Palmer. Extends northerly along the coast to San Diego 

 and San Pedro. 



VENUS (CHIONE) SUCCINCTA, Valenciennes. 



Not uncommon. San Juanico; Loreto (doubtful). Guaynms (No. 

 23592, U. S. N. M.), Palmer; La Paz (No. 34084, U. S. N. .AI.), L. Belding. 



VENUS (CHIONE) SIMILEIMA, Sowerby. 



Several specimens. 



San Quentin Bay (No. 34503, U. S. N. M.), Belding; San Juanico; 

 Todos Santos Bay (No. 74208, U. S. N. M.), Hemphill. C. succincta and 



