20 CONCHYLIA— Z>iT//yiL4. 4. 



definite species. Very numerous specimens are now in our cabinet, 

 collected from their native positions, and comparing them together, 

 Ave think that the following preserve habits and characters suffi- 

 ciently permanent to entitle them to specific distinction. 



rugosa. Saxicava testd oblongd, transversim rugosd, latere antico subangulato 



truncato hiante. 

 Shell oblong wrinkled transversely, somewhat angular open and 

 truncate at the anterior end. 



Tab nost. 2. fig. 10. 

 Mytilus rugosus Linn. Syst. Nat. p. 1156. 



Gmelin, Syst. p. 3352. 



Turton, Linn. Syst. iv. p. 290. 



Pennant, Brit. Zool. iv. p. 235, tab. 66, fig. 1. 



Da Costa, Brit. Conch, p. 223. 



Montagu, Test. Brit. p. 164. 



Donovan, Brit. Shells iv. tab. 1-11. 



Turton, British Fauna, p. 164. 



Linn Trans, viii. p. 105. 



Dorset Catal. p. 39, tab. 13, fig 5. 



Dilhvyn, Descript. Catal. p. 304. 



Turton, Conch. Diet. p. 113. 

 Mytilus lithophagus. Linn. Trans, viii. p. 270, tab. 6, fig. 3, 4. 

 Chamse pholas angusta. Lister, Conch, tab. 426, fig. 267. 

 Mus nost. From rocks in Torbay. 



Shell sometimes half an inch or more long, and an inch and a 

 half broad, but is usually about half the size, white or covered 

 with a brown skin, coarse and rough with transverse wrinkles ; 



