ZONITES. 
95 
{Alder, I. c. 107.) : Helix Helmii. Qilbertson, MSS. British 
Museum. 
Inhab. 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 magnifler) ; 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, 1821, 239. in B. M. — Helix 
radiatula. Alder ^ Cat, 12. n. 50. 1830; Mag. Zuol. and Bot. 
