142 LAND AND FRESII-WATER MOLLUSKS. 
to separate it from H. virgata , and the other 
banded snails. The shell is composed of six 
whorls, usually of a white colour, with a broad 
band around the middle of the whorl, with from 
two to six narrower ones below. 
The diameter of the shell is one inch. The 
dental formula is 
The animal is very sluggish in its movements, 
timid, and retreating within its shell on the 
slightest touch. Excessive rains destroy great 
numbers of them, as I have observed on the 
Cots wold Hills. 
It is an abundant species on the chalk and 
oolitic hills of England, and is pretty generally 
diffused throughout Ireland and Scotland. 
It has a predilection for limestone soils, though 
not confined to them, for many of the sand dunes 
around our coasts claim it. 
Helix rotundata —{the Radiated Snail) (PL 
VIII., fig. 74)—is one of our common Helices , 
and is provided with not an unhandsome shell, 
which is flattish and circular; the whorls are six 
in number, slightly convex above, more com¬ 
pressed below ; the last one is slightly angular; 
the umbilicus is very large, exposing the interior 
of all the whorls; the colour is reddish-brown, 
marked in a radiating manner with spots of brown 
and yellowish-grey; it is sometimes found trans¬ 
parent and colourless. Another variety, H. Turtoni, 
