﻿CLAMS, MUSSELS, AND OYSTERS. 



41 



A f 



Fig. 42.— Common Clam. — A. showing Siphons partly extended; in., Incurrent Orifice; ex^ 

 Excurrent Orifice ; /, Foot ; ?», thickened border of the Mantle proiecting beyond the 

 Edge of the Shell ; B, Siphons, greatly extended. (The shell is not drawn, as there was 

 no room for it on the page.) The excnrrent and incurrent orifices are more open than in A. 



