3IO JOURNAL OF CONCHOLOGY, VOL. lO, NO. ID, APRIL, I903. 



For some time, however, the name was retained in use; latterly the 

 form has been relegated to V. helvetica Blum.^ and this identification 

 has crept into literature. Many years ago the present writer began to 

 investigate the question but from lack of material was compelled to 

 let the matter bide; now, however, the question has once again come 

 up for judgment and thanks to the kind assistance of Mr. J. H. 

 Ponsonby, to whom he hereby tenders his best thanks, materials have 

 been forthcoming which enable the writer to conclude that the 

 British form, so long the subject of debate, does not belong to any 

 one of the hitherto named species and should therefore receive proper 

 designation, and he therefore proposes to name it in honour of its 

 tirst discoverer in this country: — 



VlTREA ROGERSI n. Sp. (PI. VI., figS. 2, 5, II — 13). 



Shell depressed, sHghtly convex above, a little flattened below 

 (especially in the region of the umbilicus, which is narrow, small and 

 deep), shining, very transparent, smooth and polished with obscure 

 almost obliterated lines of growth, visible under the lens, becoming 

 more marked at the suture. Colour pale horn or waxy brown, with 

 an opalascent or milky white tinge around the umbilicus. Spire but 

 little elevated, whorls five, slightly convex, increasing regularly, the 

 last having about twice the diameter of the preceding. Suture well- 

 marked and in some lights having a false appearance of being 

 channelled;^ aperture rounded-lunate, the columellar lip, which is not 

 reflexed, being in its first part not much inclined to the axis of the 

 shell, while the axis of the aperture as a whole is; peristome thin and 

 sharp, the ends slightly approximate. Dimensions : — altitude 4*5 mm., 

 diam. maj. 8*5, min. 7*5. 



It is the "■Helix glabra Stud." of Dupuy (loc. cit.) and probably, 

 though less certainly, of Moquin-Tandon.^ 



V. alliaria, Miller (PI. VI., figs. 6, 14 — 16) is a smaller shell, and 

 much flatter, especially on the underside, with a larger umbilicus, its 

 aperture is less rotund and the columellar lip more inclined away from 

 the axis of the shell; the sutures (fig. 6), moreover, do not as a rule 

 present the seemingly channelled appearance noted in V. rogersi, 

 while the whole shell is duller especially on the upper surface, is 

 greenish in typical specimens and streaked. Both V. alliaria and 

 V. rogersi have at times the strong scent as of garlic. 



V. helvetica, Blum (PL VI., figs. 3, 8 — 10), as appears from a 

 specimen from the type locality sent to Mr. J. H. Ponsonby by Dr. 

 O. Boettger, who received it from Dr. Blum, is a slightly larger shell 



1 Nac/irbl. Deutsch. Malak. Gcsellsch., vol. 30, p. 141, i88t. The species was found at 

 Weissenstein (Solothurn) where it is rare. 



2 This is due, as in /'. cellaria and some other species, to the thickened edge of attachment 

 of one whorl to the preceding showing through the transparent shell (c.f. PI. VI., figs. 4, 5). 



3 "Hist. Nat. Moll. France," vol. 2, p. 80, pi. i.v., f. 3—8. 



