130 



ANOMIA. 



ANOMIA EPHIPPIUM. LlUlU 



Mawe's Linnceus, plate \5,fig. 5, 6. 

 The Anomiae are shells without locomotive power, and 

 the animal, like that of the oyster, lives and dies on the 

 spot where its egg was hatched. They are irregularly 

 formed, inequivalve shells, always affixed to marine bo- 

 dies, particularly to the Oyster, (to which they appear in 

 some respects allied), and other testaceae, by means of a 

 small callous stony or osseous operculum, mistaken by 

 many persons for a third valve, but which in fact is only 

 the dilated and thickened extremity of the tendon or in- 

 terior muscle of the animal, forming a small solid ellip- 

 tical ossified mass, and attached to the body on which 

 these shells are affixed. It is so constructed as to close 

 the hole or notch at the summit of the flattened valve, 

 when the muscle of the animal is contracted. The per- 

 forated and smaller valve in this genus is the lower one, 

 being always placed next, and conforming to the shape 

 of the substance to which it is affixed. In the Oyster, 

 the largest and most concave is the lower valve, and 

 the contrary exists in the G. Terebratula, in which the 



