PECTEN. 



P. Plica, for the singular rugosity of the inside of 



the hin^e line. 

 P. nodosus, for the richness of its colouring and its 



singular vaulted tubercles. 

 P. Pallium, or Ducal Mantle, for its brilliancy of 



colour, and squamose surface. 

 P. histrionicus, for its pretty Harlequin coat. 

 Many of the species are remarkable for the diflFerence 

 in colouring observable in the two valves. It is scarcely 

 necessary to add that they are all marine. 



There are many fossil species, which are found in 

 most of the strata from the Crag down to the Oolitic 

 series. 



The Pectines were united with the Ostreae by Linn^, 

 most authors have however agreed in separating them : 

 they are easily distinguished by their not being attached 

 by the outside of one valve. 



