SMITH : FURTHER NOTES ON BRITISH HYDROBlA. 245 



" Oxwich Marsh, near Swansea," where, in all probability, it is 

 not found. 



{b.) He would not have stated that it consisted "of only 

 four whorls," as in If. Jenki?isi there are at least six. 



{c.) He certainly would not have overlooked the carination 

 of the last and penultimate volutions — a feature existing in the 

 majority of specimens. 



{d.) He would have mentioned its superior size. 



My opinion of Jeffreys' var. ovata of B. ventrosa, judging 

 by the description and locality, is that it is a short stumpy form 

 of that species. 



In conclusion I would point out that Frauenfeld does not 

 state that our H. similis is a BitJiynia : it is the shell described 

 by Draparnaud he refers to. 



Mr. Marshall observes that " the Cyclostonia simile of 

 Draparnaud is certainly a synonym of our shell." From the 

 original brief description and figure it is quite impossible to 

 identify his species. It is merely tradition which has handed 

 down to us the shell which we know as Hydrobia similis as the 

 true Cyclosioma simile of Draparnaud. Surely Frauenfeld would 

 not have given another name to the similis of authors, if Drap- 

 arnaud's type had been identical in all respects, excepting the 

 operculum ? Would he not have suspected that a wrong oper- 

 culum had been introduced into the specimen, although, in 

 shells of such small size, it is not likely to have occurred. 



The synonymy of H. confusa is as follows : — 

 Hydrobia confusa (Frauenfeld). 

 1 82 1 ? Valvata similis Hartmann, Syst. , Erd. and Sussw. 

 Gaster. Europ., p. 57 (in Sturm's Deutsch. Fauna 

 Abtheil. vi.). (Name only). 

 1830 ? Paludina similis Menke, Synopsis, p. 42 (name only). 

 1S31 ? jP. i'/w/Z/.y Turton, Man. Land and Freshwater Shells 



Brit. Is., p. 135, f. 121. 

 1838 ? P. similis Potiez & Michaud, Gal. Douai, vol. i, p. 254. 



