Wedge-shells, Venus-shells^ and Cockles 



41 



little beyond low-water mark. The Banded Cockle 

 (('. fasciatwni) is another minute species, with about 

 25 ribs bearing overlapping scales. The shell 

 is thinner, the valves less swollen. The name 

 is suggested by the reddish-brown bands, 

 but these are by no means unfailing marks 

 of identity, for the species is a very variable 

 one. The animal is white, with a plain-edged mantle, 

 and the long, slender, finger-shaped foot is trans- 

 parent. It is a common shell on all our coasts 

 where there is gravelly sand, in from 5 to 90 fathoms 

 of water. The Knotted Cockle (C. nodosum) is 

 similar to the Banded Cockle, swollen near the 

 beaks, with from 24 to 28 ribs, covered with little 

 knobs or oval plates. The colour is white, son:ietimes 

 tinged or banded with yellow or brown. The white 

 animal is somewhat transparent ; the mantle fringed 

 with white filaments, and the siphons pale yellow ; 

 foot white. It is generally distributed, and occurs 

 among sand and shell - gravel at depths between 



3 and SQ fathoms. 



The Common Cockle 

 {C. ediile) is so thoroughly 

 well known that it stands 

 in need of little description. 

 The shell is somewhat 

 rhomboidal, solid, and with- 

 out gloss, traversed by ribs 

 varying in number from 24 

 to 28, and by minute lines 

 right angles. The animal 

 the mantle is pale yellow, 

 white frino^e. The short 



Common Cockfe — interior 



crossing each other at 

 has a white body, but 

 its edofes with a short 



