LAND SNAILS. 
141 
this snail occurs in great plenty on the trunks of 
beech trees having a southern aspect. 
Helix obvoluta —(i the Cheese Snail) (PI. VII., 
fig. 49)—the aperture of the shell of this species 
is rather curious, and alone is sufficient to distin¬ 
guish it; it is obliquely triangular, with a tooth¬ 
like protuberance. The shell is nearly circular, 
flat above, with the spire slightly sunk, compressed 
below, and with a large umbilicus; the whorls, 
six in number, are closely wrapped together, cylin¬ 
drical, compressed from side to side, and gradually 
increasing in size; the last one is dilated towards 
the mouth. Young shells want the triangular 
mouth and reflected lip. 
The colour of the shell is reddish, with the 
epidermis raised into curved ridges, and clothed 
with short stiff brown hairs. The dental for¬ 
mula is 
The principal locality for this shell is Ditcham 
Wood, near Buriton, Hampshire; it is also found 
at Uppark and Stoner Hill, in the same county. 
In Ditcham Wood it occurs abundantly, and 
hybernates at the base of hazel trees; the 
epiphragm is thick and of a chalky-white colour. 
Helix eeicetobum —(the Heath Snail) (PI. 
VIII., fig. 68).—The shell of this species is very 
elegant, of a circular flattened form, with an ex¬ 
ceedingly large umbilicus and a nearly circular 
mouth. These characters will enable one readily 
