182 proceedings of the california 



Regular Meeting, August 21st, 1871. 

 President in the Chair. 

 Mr. W. H. Dall read the following paper : 



Notes on California MoUusca. 



BY W. H. DALL. 



Tcrebratella occ i do n tal i s, Dall. 



In examining the brachiopods in the State Geological Survey collection, 

 and other collections existing in California, my attention was directed to a 

 shell which has gone under the name of Waldheimia Gmyi of Davidson. 

 Davidson's species was originally described from Japan, and is a true Wald- 

 heimia. The Californian species is a Tercbratella, and apparently undescribed. 

 Having examined typical specimens of W. Grayi, I have no hesitation in 

 considering the Californian species as distinct and new. It may be charac- 

 terized as follows, from the type specimen of the State Geological Survey. 



Spec. char. Shell, variable in size and shade of color, usually of a flesh tint, 

 deeper on some of the lines of growth. Sculptured by radiating ribs variable in 

 number (9 in the typical specimen), with rather smooth interspaces, only crossed 

 by more or less prominent lines of growth. Hinge line long, somewhat arched in 

 the middle ; area wide, sharply carinated, flat, crossed by transverse lines of 

 growth. Apex not prominent, usually eroded. Foramen large, incomplete, 

 deltidia widely separated and differentiated from the area by deep grooves. 

 Typical specimen .75 in. long, .6 in. wide and .2 thick. Habitat, coast of 

 California. Monterey, Cooper and Dall. Catalina Island, Cooper. Cab. Cala. 

 Geol. Survey No. 6. This species closely resembles, in general appearance, 

 Waldheimia Grayi, Dav., with which it has been confounded ; but belongs 

 to a different genus. 



Ostrea virginica, Gmel. 



My attention having been called to specimens of oysters, which had been trans- 

 planted over the Pacific Railroad to the coast of California, when about three- 

 fourths of an inch long, and made during one year a large and healthy growth, 

 I observed a notable difference between the new growth and the old. The 

 Eastern species is usually characterized by a white shell, with a rather smooth 

 surface, varied by irregular lines of growth, and faint radiating ridges. The 

 new growth of the species transplanted into California waters is characterized 

 by purple radiating rays of color, and by very strong radiating folds or inter- 

 locking grooves and ridges. These latter are also characteristic of the Cali- 

 fornian native species. So it would seem as if the foreign ones had, in their 

 new abode, taken on, to some extent, the characters of the natives " to the 

 manner born." A similar peculiarity has been noticed by foreign naturalists in 



