GENUS XVI. MYTILUS. 87 



ginal, and parallel to the edge to which it is attached 

 (see Mytilus Hirundo Linn. f. 50). 

 LiNGULA. Shell flat, long, with nearly equal valves, truncated 

 before ; the hinge without teeth ; the beaks pointed and 

 united to a tendinous tube, which serves for a cartilage 

 to the shell, and fixes it to any marine substance (see 

 Patella Unguis Linn. ; Mytilus Rostrum of Shaw and 

 Turton; Chemn. 10. t. 172. f. 1675, 1676). 



The animal of this last is furnished with two very long arms, 

 ciliated, like the animal of the Anomia Terebratula. 



Lamarck does not appear to be quite correct in describing 

 Mt/tilus edulis as having only one muscular impression ; it has 

 only one large ; the others are but small, and not easily per- 

 ceived. In anatinus there are two conspicuous ones, the other 

 is obscure. 



