COLIMACEA. 83 



Med. Rep., 1821, p. 239; Sheppard, Linn. Trans., XIV, p. 

 160; Jeffreys, Linn. Tr., XIII, p. 340; Alder, Cat., p. 134, f. 

 49; lb., Mag. Zool. and Bot., II, p. 107; Thompson, Ann. and 

 Mag. Nat. Hist., VI, p. 32 ; Brown, Illust. Conch., p. 52, pi. 

 18,* f. 1, 2. 



Varieti/ 1. Helix Helmii, Gilbertson, MSS.; Alder, Local. 

 Cat., p. 1 07. 



Shell subpellucid; consisting of four and a half volutions, the 

 whole much depressed, those of the spire but little raised, and 

 defined by a very slender line, the body one rounded at the 

 sides ; apex obtuse ; base a little concave, with a large and deep 

 umbilicus, exposing the lower volutions of the spire internally ; 

 aperture semilunar ; whole surface with rather strong, longitu- 

 dinal wrinkles ; of a dull yellowish-brown above, the base more 

 glabrous, except close around the umbilicus, where it is opaque 

 and whitish. Diameter about three-tenths of an inch. 



It differs from JI. cellm'ia in being a little more convex 

 above, and somewhat more concave below. Its dull aspect 

 above is also a well marked character. The opaque white be- 

 low is not so much spread as in the former species. 



Found under stones, at the sides of hedges, in England, 

 where it is rather local, and in Ireland, where it is generally 

 diffused, Mr. Thompson gives its habitat "among mosses, in 

 glens and sheltered places ;" and adds, " from two localities in 

 this country (Ireland), I have seen Helices of crystalline trans- 

 parency, and in form intermediate between H. nitidula and H. 

 alliaria" 



34. Helix lucida, pi. IX, f. 7, 8. 



Helix lucida, Drapernaud, p. 103, pi. 8, f. 11, 12; Pfeiffer, 

 I, p. 35, pi. 2, f. 18; Von Alten, S. 72, pi. 8, f. 15; Thomp- 

 son, Ann. and Mag. Nat. Hist., VI, p. 33 ; Alder, Mag. Zool. 

 and Bot., II, p. 107 ; Turton, Man., p. 5Q, pi. 5, f. 38 ; Brard, 

 p. 34, pi. 2, f. 3, 4 ; Brown, Illust. Conch., p. 52, pi. 18,* f. 3, 

 4; Helix nitida, Gray, Med. Rep., 1821, p. 239. • 



Shell dark chocolate-colour when the inhabitant is alive, and 

 of a dark horn-colour when extracted, subdepressed ; spire 

 slightly elevated, consisting of four volutions, finely striated 

 longitudinally; base a little produced, with a large umbilicus, in 

 which the second volution is visible; aperture subrotund. Dia- 

 meter about a quarter of an inch. 



