LAND SNAILS. 
157 
to its fall length. This I have observed being 
done when there was no obstacle in the way. 
It also retracts occasionally, and apparently 
without any reason, one of its horns and not the 
other. It does not appear to be ovoviviparous, 
like P. umbilicata.” 
Pupa secale —(the Juniper Chrysalis Shell) 
(PI. IX., fig. 96).—The shell is larger and more 
tapering than that of any other British Pupa ; 
is a quarter of an inch or more in length, cylin¬ 
drical in form, and composed of eight or nine 
rounded and gradually increasing whorls, ob¬ 
liquely striated in the line of growth ; the colour 
is a light brown ; the aperture is much con¬ 
tracted by the seven laminar folds—two, and 
sometimes three, are on the pillar, two occupy 
the pillar lip, and four the outer lip; the teeth 
on the outer lip are distinctly visible on the ex¬ 
terior of the shell as white bands. The number 
of rows, and number of teeth in a row, com¬ 
posing the palatal membrane of P. secale , are 
thus—100 rows, 41 in a row; total, 4,100. 
This species is local, and chiefly confined to 
the limestone tracts of the South and West of 
England. On the oolitic hills it is very abun¬ 
dant, attached to stones or to the bare rock 
surface by a thin pellicle during the daytime: 
from the accidental adhesion of earthy matter 
to the shell, especially of the young, it may 
