216 GO'^CBYLIA—DITHYRA. 47. 



This beautiful little shell, which seems to have been known to 

 Lister as an inhabitant of our islands, but has since been over- 

 looked, we found imbedded among the rocks in the neighbourhood 

 of Torquay, to which they are slightly attached. 



The surface is always regular and never distorted : the valves are 

 equal ; and one of the auricles is nearly obliterated. The figure is 

 also different from the Pecten distortus of the same size, being 

 more regularly oval-oblong. 



The number of its rays, and their being alternately larger and 

 lesser, distinguish it from the Pecten varius, independently of its 

 constant habitation in rocks. 



Islandicus. Pecten testd suboeqvivalvi, strils numerosis rotundatis hifidis scabris. 

 Shell nearly equivalve, with numerous rounded cloven rough striae. 

 Ostrea Islandica. Gmelin, Syst. Nat. p. 3326. 



Turton, Linn. Syst. iv. p. 267. 



Turton, Conch. Diet. p. 258. 

 Ostrea cinnabarina. Dillwyn, Descript. Catal. p 256. 

 Pecten Islandicus. Chemnitz, vii. p. 314, tab. 65, fig. 615, 616. 



Lister, Conch, tab. 1057, fig. 4. 



Some specimens have, we understand, been taken on the northern 

 shores of the Scottish islands. Those from which we drew the de- 

 scription in the Conchological Dictionary, aj^pear to have been 

 brought from Newfoundland. 



