NO. 2183. NEW NORTHWEST AMERICAN BIVALVES— DALL. 411 



trifle shorter; beaks low, pustular, the prodissoconch very small but 

 distinct. Length, 4; height, 3.5; diameter, 1.5 mm. Cat. No. 

 194339, U.S.N .M. 



Santa Rosa Island, California. 



ANISODONTA? PELLUCmA, new species. 



Shell minute, white, pellucid, rounded triangular, smooth and 

 poHshed; beaks promment, dorsal slopes convexly arcuate behmd, 

 straighter in front; base arcuate, valves moderately arcuate with 

 entire margms; hinge with developed anterior and posterior laterals 

 and two cardmals, the anterior tooth bifid. Length, 2.3; height, 2; 

 diameter, 1.3 mm. Cat. No. 208475, U.S.N .M. 



Monterey Bay, California. 



The generic place of ihU minute shell is doubtful, but the form is 

 distinctly hke Eucliaris, though the hmge appears to differ. 



ROCHEFORTIA FERRUGINOSA, new species. 



Shell small, white, thm, subdonaciform, compressed, invariably 

 coated with a ferruginous layer Hke some species of Axinulus, inequi- 

 lateral ; anterior side longer, apical angle about 90 ; both ends rounded 

 base arcuate. Length, 4.5; height, 3.25; diameter, 1.5mm. Cat. No. 

 214413, U.S.N .M. 



San Francisco Bay. 



ROCHEFORTIA BERINGENSIS, new species. 



Shell large for the genus, oval, white with an olivaceous periostra- 

 cum, thin, somewhat compressed, sculptured rudely with low irregu- 

 lar concentric ridges ; inequilateral, posterior end longer, both rounded ; 

 beaks not prominent, hinge small and feeble, except that the resilium 

 and its attachments are rather large. Length, 11.5; height, 10; 

 diameter, 4 mm. Cat. No. 210951, U.S.N.M. 



Bering Island, Bering Sea (Grebnitzsky). 



ROCHEFORTIA GREBNITZSKII, new species. 



Shell small, translucent, pohshed, whitish; nearly equilateral; 

 general shape that of Bornia, but without the brilliant surface; sculp- 

 ture of fine concentric Unes visible under a glass, which render the 

 surface dull; beaks rather prominent, hinge weak. Length, 3.25; 

 height, 2.5; diameter, 1.3 mm. Cat. No. 207258 «, U.S.N.M. 



Bering Island, Bering Sea (Grebnitzsky). 



This may ultimately prove to be a Bornia. 



ROCHEFORTIA GOLISCHI, new species. 



Shell subquadrate, compressed, thin, white, very inequilateral; 

 the anterior end very short, beaks low, 1 mm. behind the anterior 



