CO^CnYLlA—DITHYRA. 38. 175 



i^und red dots, which very rarely become confluent about the mar- 

 gin and form short lines : beaks tumid and prominent, causing the 

 margin on each side of them to ajipear a little projecting, or as it 

 were slightly eared like a Pecten. 



Whether the species above described, and which were considered 

 by Linne to be distinct, will hereafter be fixed as such, better de- 

 cision than our own must determine. The bed of the British Chan- 

 nel abounds with them, some leagues from the land, where we have 

 dredged them all in a living state, and whence they are occasionally 

 wafted to the shores of Guernsea and Cornwall. 



The Pectunculus decussatus and P. nummarius seem to preserve 

 very constant characters : the first being flatter than the others of 

 the same diameter, more regular decussate and downy ; the last be- 

 ing always more tumid and prominent at the beaks ; and as far as 

 we know have not yet been discovered on the shores. 



40. ^\]GVL A— LAMARCK. 



Testa ovato-trigona vel oblonga, cequivalvis, inoequilateralis, clausa ; 

 umbonihus contiguis. Cardo dente cochleariformi ohliquh producto, 

 in utrdque valvd : lateralibus utrinque numerosis, acicularibus, recur- 

 vis, alternatim insertis. Ligamentum internum. 



