THE NAUTILUS. 



Vol.. XXVIII. MAY, 1914. No. 1 



NOTES ON WEST AMERICAN OYSTERS. 



BY WILLIAM H. DALL. 



On endeavoring to review the oysters of the Pacific Coast some 

 notes were made which seemed likely to be of use to students. 



OSTKEA IUIDESCENS Gray, 1854; Cpr. Maz. Cat., 1856. 



The brief diagnosis of the earlier name is not sufficient to identify 

 this with 0. prismatica Gray, 1825. 0. spathulata Sowerby, 1871, 

 is based on a worn upper valve of 0. iridescens. The species is 

 known to range throughout the Gulf of California and to Mazatlan. 

 I have not compared the African species listed by Carpenter under 

 the same name. 



O. MEGOUON Hnnley, 1845. (0. yallus Val., 1846, and 0. taylori 

 Gabb, 1866). 



From the Gulf of California to Peru. Fossil in the West Indies. 



O. FISIIEKI Dall, n. nom. (O, jacob&a Rochebrune, Bull. Mus., 



Paris, 189-'), not of Linne. 1758). 



Rude, dark purple, sharply plicated, with an inner purple margin, 

 valves subequal,and interior opaque white. Named in honor of W. 

 J. Fisher who made large collections in the Gulf of California and 

 Alaska. This species grows large and heavy, and is only known 

 from the Gulf of California. 



O. VEATCHII Gabb, 1866. 



Large, rather roundly plicated, internally with olive, brown stains 



