244 Mr, Gray on the Synonimay S^c. [Oct. 



England, he considered it as found on the shores of our coast. 

 Mr. Sowerby's paper not having been printed till the publication 

 of the thirteenth volume of the Linnaean Transactions, which 

 was several years after the reading of the paper, and the volume 

 of Lamarck's History containing this shell appearing in the mean 

 time, he added as a note to his paper, that Lamarck had erro- 

 neously described his shell twice over, once under the name 

 ot Discina, and again under that of Orbicuiaj and he has pub- 

 lished the same opinion in his ^' genera of shells." But with 

 this idea I am sorry that I cannot coincide, and more especially 

 so as Ferussac, in his Synoptic Table, and several others, have 

 taken Mr. Sovverby's ipse dixit for fact. To prove that the 

 Discina is not a species of Orbicula, it is only necessary to 

 inspect the beautiful plate by Mr. James Sowerby, which accom- 

 panies his brother's paper, and compare it with the figures of 

 Muller ; and I believe that most persons will allow that Muller's 

 figures agree best in the form of the muscular impression with 

 the Crania, on the before-mentioned plate; and the slit in the 

 under valve could never have escaped the accurate eye of Muller, 

 who has figured his shell with so much detail. 



It appears to be the fate of this genus that it should be confused. 

 Blainville, in his article on Mollusca,just published, has divided 

 the genus Orbicula into two sections; 1. The adherent valve 

 not pierced, O. lavis, Soio. Lin. Trails, xiii. 2. The adherent 

 valve pierced, and provided with a compressed medial apophysis, 

 Discina, O. Norvegica, Sow. Lin. Trans, xiii. when it is only 

 necessary to consult the shells or plates, for the lower valves of 

 both are exactly similar, and oddly enough the true 0. Norvegica 

 of Muller is taken no notice of. 



In accordance to these views, the genera before-mentioned 

 appear to require the following synonima; — 



1. Anomia, Bruguiere. 



Anomise Pars, Limutns. 

 Echioderma (Echion), PoH. 



2. Te R E B R A T u L A , Jhifguiere, 

 '■■** Anomia, Linnceus. 



'*■ Criopidernia (Criopus), Poli. 



To this genus may be added as subgenera Magus, Spirifer, 

 and perhaps l^roductus of Sowerby, and Gryphea of Megerle. 



3. Cram A, Brnguiere. 



Anoniiee pars, Linnaeus, 



Patella species, Muller, Montague, 



Criopidernia (Criopus), Poli. 



Orbicula, Cuvier and Lamarck, not Sowerby nor Blainville. 



Terebratula, Schweigger. 



4. Discina, Lamarck, 



Orbicula, Sotverbi/, Biainvilli,', not Lamarck. 



