24 



which a child procured for me on the beach at Par, I 

 found five specimens of the single valves. 

 D. RUBRA. Flem. Brit. An., p. 434. I have only ob- 

 tained a single valve of this rare species. 



The second division is marked by having no lateral 



TEETH. 



CAPSA. 



GENERIC CHARACTER: The Shell transverse, equal- 

 valved, close ; the hinge with two teeth in the right valve, 

 and one entering bifid tooth in the other; no lateral teeth. 

 Ligament external. 

 C. CASTANEA. Donax C. Mont. Test. Brit. vol. 2, 

 p. 573. C. C. Flem. Brit. An. p. 434. 

 Montagu observes, " It appears to be a rare species, as 

 only one mutilated specimen of a single valve had come 

 under obsesvation till very lately, which was taken at Fal- 

 mouth in Cornwall, five or six years ago ; from which we 

 did not chose to hazard a description : a few other specimens, 

 recently found at St. Austle bay in that eounty, and on 

 the coast of Devon, has enabled us to add it to the Catalogue 

 of British Shells." 



CRASSINA. 



GENERIC CHARACTER: The shell suborbicular, equal- 

 valved, with scarcely equal sides, close. Two strong 

 diverging cardinal teeth in the right valve, and two very 

 unequal teeth on the other. Ligament on the longest side 

 external. 



* C. SULCATA. Yenus S. Mont. Test. Brit., vol. 1, 

 p. 131. Astarte S. Flem. Brit. An., p. 439. It is in- 

 troduced on the authority of Da Costa. 



* C. DANMONIiE. Astarte D. Flem. Brit. An., p. 440. 

 Fleming describes the shell as white, with a dark brown 

 cuticle; but I have seen it no otherwise than a dull 

 yellow. Common in the trawl, at Falmouth. 



C. TRIANGULATA. British Museum. Length about a 

 line, form nearly triangular, with the margin rounded, 

 toothed at the meeting of the valves; beaks prominent; 

 valves smooth, with concentric lines, not raised into fur- 

 rows. Colour pale yellow. Rare. 



SECTION III. 



CONCHIFERA L A M EL LIP ED A, 



Foot of the animal broad and thin. 



CONCHjE. 



With three cardinal teeth at least in one valve, and as 

 many or less in the other ; sometimes with lateral teeth. 



