OF CONCHOLOGY. 319 



NOTE ON GADINIA AND ROWBLLIA. 



BY J. G. COOPER, M. D. 



In Mr. Ball's late article on Cfadinia he founds his description 

 wholly on the species which is the type of Roivellia, and assumes 

 that all former investigators must have been mistaken, because 

 their types did not agree with that before him. A naturalist as 

 cautious in associating similar shells without comparing the soft 

 parts, might have better hesitated before asserting that Dr. Gray, 

 Dr. Philippi and the Adams were all mistaken, because there is a 

 similarity iii the sliells of the species described and figured by 

 them, to the one which he has alone examined. It is certainly 

 not proved by his assertions that the species are congeneric. 



The young living specimens found by me at Catalina Island, on 

 which I founded Rotvellia, were living on the under sides of 

 stones, between tides, and were submerged during part of the 

 day. Not liaving means for more than a sketch of their ex- 

 ternal form I made one, resembling that on plate 2, fig. 6. The 

 tentacles in this appear as if "pectinated" or divided in a ser- 

 rate manner. On comparison of this with the animal figured 

 by the Adams as a G-adinia, (which we may suppose was drawn 

 by one of them from life, while on one of his tropical collecting 

 tours), the difi'erences are so marked that I proposed the sub- 

 genus Rowellia for our species, in honor of the zealous concholo- 

 gist who first obtained it in California. Now, according to Mr. 

 Dall's own table of synonyms, all preceding names were founded 

 on the Mediterranean species (except, perhaps, Muretia^ D'Orb., 

 preoccupied by Gray as Mouretia.) It is, therefore, still to he 

 proved that Roivellia, of which the anatomy is so well described 

 by Dall, is not a good genus. 



As to its specific identity with the tropical " Gr. reticulata^ 

 Sby.," I will not pretend to decide, but as that species is "reti- 

 culate" above, and ours simply radiately ornamented or ribbed, 

 (with occasional concentric lines of growth crossing the rays), it 

 appears safest to consider them distinct until better means of 

 comparison are offered. In the Fissurellidce great importance 



