CONCHY LI \—DlTHYR A. 40. l7o 



round red dots, wliicli very rarely become confluent about the 

 margin and form short lines : beaks tumid and prominent, caus- 

 ing the margin on each side of them to appear a little projecting, 

 or as it were slightly eared like a Pecten. 



Whether the species above described, and which were consi- 

 dered by Linne to be distinct, will hereafter be fixed as such, 

 better decision than our own must determine. The bed of the 

 British Channel 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 pre- 

 serve very constant characters : the first being flatter than the 

 others of the same diameter, more regular decussate and downy ; 

 the last being always more tumid and prominent at the beaks ; and 

 as far as we know have not yet been discovered on the shores. 



40. N\JCVL\— LAMARCK. 



Testa ovato-trigonok vel oblonga, (eqidvalms, ino'quilateralis, 

 ctausa ; mnbonibus contiguis. Cardo dente cochleariformi 

 oblique producfo, in utrdque valcd : lateralibus ulrinque 

 numerosis, acicularibus, recurvis, alternatim insertis. Liga- 

 mentum internum. 



