581 



indeed, this valve would not be dlfcriminated from that 

 of y4. Ephippium, if found detached from the other, be- 

 ing always dellitute of flricc. It is evident, therefore, 

 thofe who have defcribed the flat valve, muft have mif- 

 taken for it, the flatted of the concave valves that have 

 been fomcwhat worn, as Da Costa exprelfes it, "the 

 " outfide work is generally more obfolete." We have 

 recently taken alive, a few larger and ftronger fpeci- 

 mens, on the fouth coafl of Devon, adhering to old bi- 

 valves, (about an inch and a quarter in diameter,) which 

 confirms our opinion. 



All the Anomics are fubjeft to fuch variation in growth, 

 that it is impoflible to fix permanent fpecific charafters 

 to many of them, and we fufpeft the exotic fpecies are 

 multiplied beyond their natural limits. 



When we gave the A. Squarnula as diftinft, it was 

 more from popular opinion, all of which feems to have 

 flowed from Linnaeus; we muft, however, acknow- 

 ledge, that if the Squarnula is continued as diflinft, we 

 fhall in all probability never find theyoung of the Ephip- 

 pium ; if, therefore, the fynonyms of Squaviula as well as 

 Cepa, were conjoined to thofe of Ephippium, no vi- 

 olence would be offered to nature, for there really are 

 no diftinsuifliable charafters. 



O"^ 



MYTILUS. 



Mytilus edulis. Don. Br. Shells, iv. t. 128. f. 1. 1. Edulis. 



Mytilus p. 159. 



