HELIX. 63 



longer than broad. Peristome thin, and not reflected, the 

 columellar portion somewhat dilated, margins approximate. 

 Umbilicus very large and deep, displaying three or four of 

 the volutions. 



The diameter is generally four-fifths, occasionally five- 

 sixths, of an inch, whilst the height rarely attains to four 

 lines. In some of the smaller varieties the spire is more 

 elevated than in the typical forms. 



The animal is pale, greenish or greyish, darker on the 

 neck and head. 



This snail prefers calcareous soils, and is in many places 

 abundant on sandy shores, especially near the sea. It is 

 widely diffused through the British isles, ranging to the 

 north of Scotland. 



H. obvoluta, Miiller. 



Orbicular, of an uniform brown ; spire concave ; umbilicus 

 spread ; peristome reflected. 



Plate CXVII. fig. 1, 2, 3. 



Helix obvoluta, Muller, Hist. Verm. pt. 2, p. 27. — Lindsay, Trans. Linn. Soc. 



vol. xvi. p. 765. — Jeffreys, Trans. Linn. Soc. vol. xvi. p. 510. 



—Gray, Manual L. and F. W. Shells, p. 139, pi. 11, f. 131. 



— Brown, Must. Conch. G. B. p. 53, pi. 18*, f. 13, 14 



Ferus. Prodrom. Moll. No. 107 ; Hist. Moll. Terr, et Fluv. 



pi. 51, f. 4 (Helicodonta). — Lam. (ed. Desh.) Anim. s. Vert. 



vol. viii. p. 63. — C. Pfeif. Deutsch. Land und Siisswas. Moll. 



pt. 1, p. 41, pi. 2, f. 28. — Blainv. Man. Malacolog. p. 461, 



pi. 40, f. 7. — Rossmassl. Iconog. Land und Siisswas. Moll. 



pt. 1, p. 69, f. 61. — Desh. in Ferns. Hist. Moll. p. 16.— 



Chemn. (ed. Kust.) Conch. Cab. pi. 64, f. 13, 14, 15. — L. 



Pfeif. Monog. Helic. vol. i. p. 413. 

 „ ti-igonophora, Lam. Journ. Hist. Nat. pi. 42, f. 2. 

 Helicodonta obvoluta, Risso, Hist. Nat. PEurope Mer. vol. iv. p. 65. 

 Trigonostoma obvolutum, Fitzing. Syst. Verz. Erzh. Weichth. p. 98. — Hartm. 



Erd und Siisswas. Gasterop. pt. 1, p. 14, pi. 6. 

 Gonostoma „ Held, Isis, 1837, p. 915. 



Vortex obvoluta, Beck, Index Moll. Mus. Christ. Frid. p. 29. 



