OF CONCHOLOGY. 19 



the animal of the anomia attaches it- 

 self to stones, and other marine ex- 

 traneous bodies ; it is in general situ- 

 ated in the flat valve, thouo-h there 

 are a few exceptions to the contrary. 

 Plate 1st, fig. 7th, m. 



Hinges is the point by which bivalve 

 shell are united, it is formed by the 

 teeth of the one valve inserting them- 

 selves between those of the other, or 

 by the teeth of one valve fitting into 

 the cavities or sockets of the opposite 

 valve. 



It is on the peculiar construction of 

 the hinge that the generic character 

 of Bivalve shells is principally founded, 

 together with the general contour of 

 the shell. Plate 2nd, figures 1st and 

 3d, qqq. 



Teeth of the Hinge. Upon the 

 number and relative situation of the 

 teeth, principally depend the specific 

 distinctions ; they are of various 

 forms, and very differently placed ; 



