428 Bemarks on British Land and Fresh-water Shells. 



Helix celldria (w), nkida{x). — Are these really distinct, or 

 only the same shell in different stages of growth ? 



Jrielix rtifescefis {y), Eng. auth. — This common shell seems 

 to be extremely ill understood. Is it referable to none of the 

 numerous species described and figured by Draparnaud ? Cir- 

 cumstances which have tended to render it more confused, are, 

 that English authors have followed each other in describing 

 the immature shell to be hairy, and that the figure given by 

 Donovan, plate 151. f. 1., under the name of HeYiyi hispida, 

 is the H. rufescens in a young state (z). The two shells are 

 doubtless specifically distinct ; the H. rufescens is keeled on 

 the margin of the outer whorls and smooth, the other rounded 

 and hispid. It has been imagined that these hispid shells lose 

 their hairiness, and add a keeled whorl to their former rounded 

 ones, on arriving at maturity. This is fallacious. By care- 

 fully removing the whorls of the H, rufescens with a knife, it 

 will easily be perceived that they are all keeled. I possess 

 specimens from one to seven lines in diameter. The small 

 ones are as distinctly keeled as the large. Observations of a 

 similar nature have also been made by my friend, Mr. William 

 Helm, a most successful and industrious collector here. 



\rielix hispida (aa). — This species I take to be the hairy one, 

 confounded with the Helix rufescens. Does the H. ^urturum 

 of Gmelin belong to this or the last ? 



Helix sericea, Drap.(5^). — I consider this the shell called 

 Helix hispida by Turton, and several other English writers. 



A'nodon intermedins, 

 {fg. 185.) — Is this 

 an English species ? 

 The Mytilus stagna- 

 lis, dentatus and avo- 

 nensis of Turton, &c., 

 are ill understood ; and 

 some of them may, 

 really distinct from the 

 A. cycneus and «nati~ 

 nus, be referable to this 

 species. 



iTie number of indigenous land and fresh-water species, 

 appears to be between 100 and 120, of which I and one or two 

 other friends have collected about 60 species in this neigh- 

 bourhood. Several described as rare, occur in tolerable abun- 

 dance, whilst others which are represented as plentiful, have 

 hitherto eluded our researches. I fear that a list of those dis- 

 covered would be too unimportant to trouble you with, but 

 should you be of a contrary opinion, it will be at your service. 



