ANOMIA. 



means of its muscle with the peg or appendage; whereas 

 the other two are in like manner coimected by means of 

 their muscle with the single muscular impression in the 

 lower valve. Ligament internal, transverse, placed just 

 l^ithin the umbo in the larger valve, and to a projecting 

 and transversely expanding appendage quite at the base 

 of the flatter valve. 



This, like all other irregular attached shells, is 

 usually modified in form according to the substance 

 to which it has adhered to, which circumstance ren- 

 ders it extremely difficult to decide upon what may 

 or what may not be considered as specific characters, 

 the natural consequence of which is that many, mere 

 varieties on account of their situation, have been raised 

 to the rank of species, and described as such : notwith- 

 standing which, we are persuaded that our British species 

 may be reduced to two or three at most : with respect to 

 foreign species, we can say but little, because they are 

 scarcely ever brought home in a state of perfection, or if 

 they be, they are destroyed by the dealers as of no value. 



Very few fossil species are known ; they are, how- 

 ever, found, though rarely, in the Crag and London Clay, 

 in England; and in the marine formations above the, 

 Chalk, in France. 



Fig. 1. j4nomia Ephippiuniy outside of the attached valve, 



2. inside of the s$me. 



3, ■■ - inside of the upper valve. 



J. I 



