'ZONITES. 95 



(Alder, 1. c. 107.) : Helix Helmii. Gilbertson, MSS. British 

 Museum. 



Inliab. hedge sides, under stones, &c. 



Animal dark lead-colour. {Sturm, t. 12.) 



Shell about three tenths of an inch in diameter. 

 Differs from Z. cellaria in being smaller, rather 

 more convex above, and more concave beneath ; of 

 a dull lustre, darker colour, and more strongly 

 wrinkled above ; the umbilicus is larger, and the 

 aperture set at a less oblique angle ; the opaque 

 white, also, is not so much diffused over the base of 

 the shell, but it is confined to the edge of the umbi- 

 licus. The animal is of a darker colour. (Alder.^ 



Mr. Gilbertson thinks that there are some pecu- 

 liarities in the habit of the animals, together with 

 the white colour of the variety of the shell, which 

 induces him to consider Z. Helmii as distinct from 

 Z. nitidulus, but as yet he has not published his ob- 

 servations on it. 



29. 5. ZoNiTES radiatulus. Rayed Snail. — Shell 

 depressed, horn-coloured, rather shining, trans- 

 parent, regularly striated ; 3^ or 4 whorls, flat- 

 tened at their junction with the inner ones, 

 over which the striae appear continuous and 

 strongly marked, giving the shell a radiated ap- 

 pearance (under a magnifier) ; the outer whorl 

 rather large in proportion to the rest, under 

 side smooth, without any whiteness ; umbilicus 

 moderately large, (t. 5. f. 50. ? t 12. £ 137.) 



Helix striatula. Gray, Med. Repos, 1 821, 239. in B. iJ/.— Helix 

 radiatula. ^Wer, Cai. 12. n. 50. 1830; Mug. Zuol.and Bot. 



