45 



A. fornicata and A^ coronal a recorded by Mr. Bean, but I 

 learn from the ' British Mollusca' that they fall into the same 

 category with those I have named. 



I have now noticed all the varieties of A. ephippium termed 

 by authors species, and there is certainly no sculpture on 

 them of such a decided character as to denote specific distinc- 

 tion; therefore all the markings^ shapes and colours of this 

 Protean genus being inadequate for the foundation of species, 

 we must have recourse to our sheet-anchor the malacology 

 of the animal to assist our determinations; and after the 

 examination of a great number of individuals, of nearly all 

 the recorded species, we have come to the conclusion that 

 they are varieties of the only British one of this genus, the 

 A. ephippium, which, by the identity of its organs with the 

 pseudo-species, puts a veto on a longer continuance of the 

 dismemberment of its unity, by allowing forms based on mere 

 varietal distinction to march pari passu with it, and which 

 have no solid grounds for aspiring to higher honours. 



PECTINHLE. 



The British Pectinida comprise only the genus Pecten, 

 which is a part of Lamarck's monomyal order. The genus 

 Lima, usually associated with Pecten, is merged in it as a 

 section. Our reasons for distributing the Anomia, Pectines, 

 and Ostrece in three families, are given in our remarks on 

 the Anomiadce, wherein the essential points of the differences 

 of the organs and habitudes of their animals are shown ; we 

 may add, that the texture of the shells of this group has lost 

 the leafy imbricated character and become firmer, solid, and 

 of a more porcellanous nature ; their form is infinitely more 

 symmetrical than in either Anomia or Ostrea. A careful 

 examination of the descriptive notes of the animals of the 

 Pectinidte will show that they are not of the same family as 

 either of the other groups. 



