OF CONCFIOLOttY. 190 



It presents, in my opinion, a " distinguishable variation" from 

 those of "P. exarata," Rve., on pi. 19, and its synonym "P. 

 tindato-lirata, live., on pi. 23. 



Soon after I commenced collecting at the Hawaiian Islands, 

 some twenty years or more past, I remarked that the native3, in 

 speaking of the common limpet, made use of two specific names.* 

 Inquiring whether they supposed the two were distinct species, 

 they answered by bringing me specimens, and pointed out the 

 difference, which proved they were correct. 



The. shell of "P. Sandwichensis," Pse., is thicker, more ele- 

 vated, ribs generally larger, wider apart, more prominent,"and 

 crenate or scabrous and usually with a smaller intermediate rib. 

 The color of the interior also differs. I find among my papers 

 the drawing and description of the animal of but one species, and 

 will not trust my memory to compare the two. 



The description of the animal by Mr. Dall does not corres- 

 pond with that of either species. 



The two species differ also in their habits and station. "P. 

 Sandwiche nsis" lives at low water mark, and is consequently 

 usually coated with lime. I suspect it breeds there also, in the 

 fissures and holes of the rocks. 



"P. exarata" lives at high water mark, and breeds, where the 

 locality admits of it, in shallow water. 



Immature specimens of the latter vary much in color and 

 somewhat in shape. They are spotted with green and black, or 

 spotted and striped with various colors. "P. opea, Nutt. MSS., 

 is one of the varieties. As they mature and pass out to the surf, 

 their characters become more constant. From thence they go 

 off into deep water, 5 to 10 fathoms, where they attain to a size 

 twice that figured by Mr. Reeve. Specimens are seldom ob- 

 tained, as our natives have given up the practice of diving in 

 deep water. They assure me that they are the same species as 

 those living on the reef, which, however, cannot be positively de- 

 termined until the animals are compared. 



Among the papers overlooked by Mr. Dall, is one by Prof. Edw. 



*The natives of Polynesia, and probably those of other countries make 

 use of the binomial nomenclature for plants and animals, especially such 

 as aremade use of for food, &c. Transient collectors fall into error oc- 

 casionally, when they adopt the name given them by the natives as a 

 specific one, whereas the natives almost invariably give the generic name. 

 An amusing error occurs in "Voy. au. Pol. Sud," where Mr. Hombron has 

 named a species of Helix "Vahine," which means a " female," or grown 

 up woman or other animal. His species, therefore, stands as the female 

 Helix. 



I note the above facts to prove the absurdity of adopting native names, 

 in any branch of natural history. 



