ANIMAL REPRODUCTIONS, 238 
éount of the continual extenfion and contra¢tion, 
the fwelling and diminifhing of the cone when 
the {nail is in motion. I have commonly found, 
that the head extends from the obtufe extremity 
of the cone to about a line beyond the larger 
horns, when the {nail ftretches to the trie 
from the fhell, and there the fetion may be 
made fo as fecurely to take away no more than 
the head. But if thefe limits be pafled, fo as to 
cut off fome part of the body along with the 
head, then we are alnioft certain of the animal’s 
death. 
The fnails on which my experiments have 
been made with the greateft fuccefs are of three 
{pecies 3 the Helix pomatia, nemoralis, and luco- 
rum, to avail myfelf of the appellations of the 
nomenelator, Linnzus. Several of one {pecies 
aré defigned, Plate 6. Fig. 1. The fnail in its 
hell, but preparing to come out. Fig. 2. It be. 
gins to difplay the head and horns. Fig. 3. The 
horns fully extended; the fnail feen rahe be- 
low. Fig. 4. The {nail as far out of the fhell as 
poffible. Fig. ei A portion of the cone com- 
prehending the head only, which, for better illuf- 
tration, is reprefented fevered from the neck. 
Fig. 6. The decapitated fnail: four points ap- 
pear on the trunk denoting the fite of the four 
horns; 
ae After 
