Involute.] 



MOLLUSCA. 



45 



Sub-Gentis 2 Helicigona Ferussac. 



Shell orbicular, depressed, equally convex both above and 

 below; umbilicate ; provided with a carina on the centre of the 

 body ; aperture tra?isverse ; lips united all round. 



7. Helix lapicida, pi. XVII, f. 9, 10, 11— First Ed., pi. 

 40, f. 9, 10, 11. 



Helix lapicida, Linne, Syst. Nat., p. 1241 ; Gmelin, Linn. 

 Syst., p. 3613, No. 2; Miiller, Verm., II, p. 40, No. 240; 

 Donovan, Brit. Sh., II, pi. 29, f. 2 ; Pennant, Brit. Zool., IV, 

 p. 132, pi. 83, f. 121 ; Drapernand, p. 1 11, pi. 7, f. 35, 36, 37; 

 Braid, p. .53, pi. 2, f. 14, 15; Fleming, Edin. Ency., VII, p. 

 80; Brown, Ency. Brit., 6th Ed., VI, p. 457; Rossmassler, I, 

 p. 63, pi. 1, f. 1 1 ; Caracolla lapicida, Lamarck, An. San. Vert., 

 VI, pt. 2nd, p. 99 ; Fleming, Brit. An., p. 258 ; Alder, Mag. 

 Zool. and Bot., IT, p. 109; Turton, Man., p. 66, pi. 5, f. 51; 

 Helicigona lapicida, Ferussac, Prod., p. 1 50, pi. 66,* f. 6 ; 

 Chilotrema lapicida, Leach, Moll., p. 106; Helix acuta, Lister, 

 Conch., pi. 3, f. 4 ; Da Costa, p. 55, pi. 4, f. 9. 



Shell depressed, subdiscoidal, equally convex above and 

 below ; body large ; spire short, consisting of five much flat- 

 tened, slightly ventricose volutions, terminating in an obtuse 

 apex ; body with a central, sharp-edged carina, which emanates 

 from the margin of the outer lip, and investing the body, 

 continues spirally at the base of the superior volutions, and 

 defines them by a fine thread-like ridge ; whole shell with 

 strong, wrinkled, longitudinal stria?, its entire surface presenting 

 a shagreen-like aspect ; base provided with a large and deep 

 umbilicus, exhibiting the spiral convolutions; aperture broad, 

 subovate, with a sharp margin; outer lip white, reflexed, and 

 continuous with the pillar lip, which is a little spread on the 

 base of the body, and both lips disunited from the body. 



This species is extremely local, and appears not to extend 

 much further north than the centre of England. It has never 

 been found in Ireland, according to the account of Mr. Thomp- 

 son. Its favourite habitat is limestone rocks and chalky soil. 



Sub- Genus 3 A m plexus. — Brown . 



Shell depressed, with an orbicular aperture; peristome con- 

 tinuous and reflexed ; epiphragm membranaceous. 



8. Helix pulchella, pi. XIV, f. 76, 77. 



Helix pulchella, Miiller, Verm. Hist., II, p. 30, No. 232 ; 

 Drapemaud, p. 1 12, pi. 7, f. 33, 34 ; Pfeiffer, I, p. 43, pi. 2, f. 

 32; Brard. p. 56, pi. 2, f. 9; Alder, Mag. Zool. and Bot., II, p. 

 109; Thompson, Ann. and Mag. Nat. Hist., VI, p. 23; Forbes, 

 Mai. Mon., p. 9; Rossmassler, VII, p. 5, pi. 51, f.440; Turton, 

 Man., p. 63, pi. 5, f. 49 ; Amplexus paludosus, Brown, Illust. 

 Conch., 1st Ed., pi. 41, f. 76, 77. Helix pulchella, Brown, 

 Ency. Brit., 6th Ed., VI, p. 459 ; Helix paludosa, Da Costa, 

 Brit. Conch., p. 59; Walker, Test. Min. Rar., f. 22; Montagu, 

 Test. Brit., p. 440 ; Maton and Rackett, Linn. Tr., VIII, p. 

 193, pi. 5, f. 5; Turton, Brit. Fau., p. 188; Brown, Wernerian 

 Mem., II, p. 524 ; Fleming, Edin. Ency., VII, p. 80 ; Turbo 

 paludosus, Turton, Conch. Diet., p. 228 ; Zurama pulchella, 

 Leach, Moll., p. 108. 



Shell smooth, white, subpellucid ; spire depressed, consisting 

 of three rounded volutions, well defined by the sutural line, 

 terminating in an obtuse apex, and very little elevated above 

 the body; body large, elegantly rounded, with a wide and deep 

 umbilicus at its base, exhibiting the convolutions of the spire 

 inside ; aperture circular, with an opaque, white, flattened, re- 

 flected, thickened margin ; the lips not quite meeting on the 

 base of the body. Diameter one-tenth of an inch. 



This elegant little species is pretty generally diffused through- 

 out Great Britain and Ireland. Its favourite habitat being 

 under stones, in dry situations. It is generally more numerous 

 in dry situations around the coast. It is exceedingly numerous 

 at Carolina Park, near Edinburgh ; also on the sand hills at 

 Portmarnock Rabbit Burrow, and Thompson says he found it 

 on the short pastures, in some of the islets, of Loush Strang- 

 ford, Ireland. It is, however, found in inland situations. 



Many authors consider this and the following species merely 

 as varieties ; but we have invariably noticed a difference in the 

 animals. 



9. Helix crenella, pi. XIV, f. 78, 79 First Ed., pi. 



41, f. 78, 79- 



Helix crenella, Montagu, Test.. Brit., p. 441 ; Amplexus cre- 

 nellus, Brown, Illust. Conch., 1st Ed., pi. 41, f. 78, 79; Helix 

 pulchella, var., Drapemaud, p. 112, pi. 7, f. 30, 31, 32; Helix 

 costata, Miiller, Verm., p. 31, No. 233; Pfeiffer, I, p. 41, pi. 2, 

 f. 31; Gmelin, Linn. Syst. Nat., I, p. 3633, No. 67; Alten, 

 Erd-und Flussconchyl., S. 60, pi. 6, f . 1 1 ; Gartner, Conchy!, 

 der Wetterau, S. 26; Rossmassler, VII, p. 5, pi. 31, f. 439; 

 Fleming, Brit. An., p. 263; Helix pxdchella, var., Alder, Mag. 

 Zool. and Bot., H, p. 109; Forbes, Mai. Mon., p. 9 ; Turbo 

 helicinus, Lightfoot, Phil. Trans., 1776, pi. 3, f. 1 to 4. 



Shell milk-white, subopaque ; spire depressed, consisting of 

 three well defined, rounded volutions, and terminating in an 

 acute apex, which is but little elevated above the body volu- 

 tion, and beautifully rounded ; its base provided with a large 

 and deep umbilicus, exposing in its cavity the inner sides of the 

 volutions of the spire; aperture circular; the outer and pillar 

 lips continuous, smooth, white, opaque, and reflected, but a 

 little separated on the columella ; whole surface covered by 

 numerous, strong, regular, longitudinal, concentric ribs. Dia- 

 meter one-tenth of an inch. Some specimens have a yellowish- 

 brown epidermis. 



Some authors affirm that this species is always found in damp 

 situations, while the habitat of H . pulchella is constantly in dry 

 localities. We have met with both shells plentifully in Caro- 

 lina Park, near Edinburgh, and also at Portmarnock, Ireland. 

 In the former locality, however, we always met with the two 

 species in separate situations. 



This shell is as widely spread as the //. pulchella, both in 

 England and Ireland, and in the same kind of habitat. In the 

 North of Ireland, Mr. Thompson says this species is more 

 common on dry sea banks than the H. pulchella. Forbes has 

 found the H. crenella on walls in the Isle of Man, and I have 

 met with it in a similar locality, in the King's Park, at Edin- 

 burgh. I have likewise observed both specimens in damp 

 situations, but very rarely. 



