264 CARDIID.E. 



cardia coralliophaga of Lamarck, a native of the West- 

 Indian seas, which burrows in corals and madrepores. 

 The usual habitat of C. lithophagella is in crevices of 

 rocks j but the irregular and often distorted shape of the 

 shell induces me to believe that it does not perforate them. 

 Young shells are not much unlike Cyamium minutum of 

 a comparatively large size, and are nearly of the same 

 colour ; but they are flatter, and the hinge-process and 

 scars are quite different. It is possible that Montagu 

 may have described the young of C. lithophagella under 

 the name of Donax rubra, which he said was very rare 

 and had been taken " amongst coralline in deep water/' 

 The D. rubra of Turton is the fry of D. trunculus. 1 hope 

 this notice may induce conchologists to search for C. 

 lithophagella on our southern coasts, and especially in 

 the Channel Isles. 



Family XI. CARDI'ID^, Broderip. 



BODY globular or roundish-oval: mantle widely open in 

 front, and forming two short and usually contiguous tubes at 

 the posterior or larger end : gills two on each side, unequal : 

 foot very large and conical, much bent in the middle : byssus 

 rarely produced. 



SHELL equivalve, ventricose, with a triangular outline, 

 generally somewhat equilateral, sculptured by longitudinally 

 radiating ribs or striae, and in most cases also with concentric 

 plates or foliations, which form spines, tubercles, or vaulted 

 scales ; umbonal area prominent : ligament quite external, 

 placed on the posterior side, and in some cases continued under 

 the beaks to the other side : hinge short but thick, furnished 

 with one or two rather small but strong and conical cardinal 

 teeth in each valve, besides lateral teeth, but the latter are 

 sometimes wanting or inconspicuous : pallial scar entire : 

 muscular scars oval and distinct. 



We are now in smooth water, and not sorry to have 

 escaped from the troubled sea and short broken waves, 



