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ANOMIA; Linn. 
Gen. Char. An irregular bivalved Shell: with 
a foramen in the flatter valve that allows the 
passage of a bony appendage by which the 
Animal is attached to marine substances; 
beaks none or very short. 
All the species of this genus have one valve nearly 
flat, and exactly conforming to the surface it is applied 
to and where it is fixed by the bony appendage termina- 
ting one of the muscles that is united to the other valve : 
this appendage is often termed an operculum ; it exactly 
closes the hole in the valve it pervades, which can never 
be opened by the animal, since the convex valve is the 
only moveable one : the hinge is a small ligament con- 
tained within the beak of the convex valve, and attach- 
ing the margin of the other to it. The convex valve 
alone may be known by three approximating muscular 
impressions nearly in the centre of it. 
This Genus is so easily recognized, that it is remark- 
able LinnOus should have comprehended the modern 
Genus Terebratula with it. It is unfortunately named. 
