HELIX. 81 



ami a half, of very gratlnal increase, depressed, deeply 

 defined, the last somewhat angulated, but not particularly 

 deflected. Spire merely convex. Aperture small, usually 

 occupying two-fifths of the base, rather depressed, but 

 nearly as high as it is broad, lunate. Peristome simple, 

 acute, not reflected. Base convex, excavated by an ex- 

 tremely large and profound umbilicus which exhibits the 

 superior volutions. 



The spire in the variety Turtoni is quite flattened. A 

 transparent and colourless variety is occasionally, though 

 rarely, to be met with. 



Ordinary diameter a quarter of an inch. 



The animal is bluish, with dusky neck and tentacles. 

 Up the sides of each upper tentacle runs a dusky line fading 

 away on the neck. The foot is short behind, tapering and 

 not truncated at the end. The relations of this animal are 

 with the typical Helices, and not with the group Zonites. 



This species is found under stones abundantly in all parts 

 of the British Isles. 



H. UMBiLicATA, Montagu. 



Small, dark brown, unpolished, merely wrinkled ; whorls five, 

 of slow increase ; umbilicus large ; mouth small ; outer lip acute, 



Plate CXXI. fig. 7, 8. 



Helix umhUicafa, Mont. Test. Brit. p. 434, pi. 1 3, f. 2. — Maton and Rack. 

 Trans. Linn. Soc. vol. viii. p. 200. — Dorset Catalog, p. 54, 

 pi. 19, f. 24. — TuRT. Conch. Diction, p. 54. — Fleming, 

 Brit. Anim. p. 262 (not note). — Jeffreys, Trans. Linn. 

 Soc. vol. xvi. p. 342. — Thompson, Ann. Nat. Hist. vol. vi. 

 p. 31.— Brown, lUust. Conch. G. B. p. 51. 

 „ riipestris, Chemn. (ed. Kiist.) Conch. Cab. pi. 89, f. ?>2 to 35, 40 to 43.— 



Pfeif. Alonog. Helic. vol. i. p. 86. — Draparn. Moll. Terr, et 



Fluv. France, p. 82, pi. 7, f. 7, 8, 9.— Ferus. Prodrom. 201; 



Hist. Moll. Terr, et Fluv. pi. 80, f. 2, 3.— Turt. Manual L. 



and F. W. Shells, p. 60, f. 45. — Lam. (cd. Desli.) Anim. s. 



VOL. IV. M 



