24 POPULAR BRITISH CONCHOLOGY. 



3. F. parva: shaped something like P. dacfi/his, but having 



one narrow dorsal plate. 



4. P. Candida : more oval than P. parva, with a broader 



dorsal plate. 



5. P. striata: rather conical, closed by extended edges, and 



by a squarish dorsal plate, as well as by a longitudinal 

 narrow plate back and front. Found on the coasts of 

 Great Britain and various parts of the Atlantic, in 

 floating wood, particularly mahogany. Mr. Cuming 

 also found specimens of apparently the same species 

 on the shores of the Philippine Islands. 



PHOLADIDJE. 



(Pholas Papyeacea, the Paper Pholas, PI. Ill, fig. 7.) 

 This is the British representive of the cup or tube-forming 

 Pholades. It is a beautifully delicate shell, and so different 

 in its young state to its more natural condition that it has 

 been distinctly named as a separate species. When young 

 it is similar in form to P. crispiata, but of a much lighter 

 texture. The two parts of the surface are divided by an 

 oblique line, on the anterior side of which there are nume- 

 rous prickly points, and on the hinder side only smooth 

 ridges. The opening in front, or the "anterior gape," is 



