Remarks on British Land and Fresh-water Shells. 425 



to mention will be those of Lamarck, when not otherwise dis- 

 tinguished. 



Nerithia virginea {fig.\S2.a). — Is not this a fresh- water 

 shell ? Yet Dr. Turton describes it as found on the western 

 coasts of Ireland. Will not Dr. Turton's shells, from their 

 locality and diminutive size, prove another species ? 



182 



Valvdta piscindlis (b). — Along with tbis species, of the 

 usual magnitude, I have found dead shells, four lines in 

 length (c), and several smaller ones of various sizes (d), agreeing 

 pretty well with the species V. planorbis, V. ossirorbis, and 

 V. minuta of Draparnaud, and which I have little doubt are all 

 the young of the V. piscinalis in different stages of growth, 

 although Lamarck refers to them as distinct. Mr. Dillwyn is 

 evidently wrong in considering this species to be the Turbo 

 thermalis of Linnaeus. The latter author describes his shell 

 to, be only a " little larger than a cabbage seed." The vague 

 descriptions of authors often tend to confuse. Dr. Fleming, 

 in the History of British Animals, just published, in his spe- 

 cific definition of this shell, characterises it as possessing " a 

 large central cavity^' but in his general description, a few lines 

 lower, he says, " central cavity distinct, but not large" 



Lymnceafragilis, Fleming {e), — This must be the BuUmus 

 fragilis of Lamarck, who, it evidently appears, has arranged 

 this shell among his Bulimi, in consequence of not knowing 

 the habitat. He states his specimen to have been received 

 from Dr. Leach. 



Lymncjea detrita, Fleming (jT). — Does Lamarck include 

 more than one species under his Bi\limus radiatus; and, if so, 

 is not this one ? 



Lymnce'a ovdta (g). — What I consider to be this shell occurs 

 in tolerable abundance in this neighbourhood. My speci- 

 mens, several of them an hich in length, agree with the 

 figures given by Draparnaud, but Lamarck describes his shell 

 to be only 6J lines long. Is this the large variety of Helix 

 p^tris mentioned in Dr. Turton's Conchological Dictionary P 

 What is the Helix piitris of Linnaeus ? Is it this shell, the 

 Lymnae^a peregra, or the Succinea amphibia ? 



Vol. I. — No. 5. g g 



