8 THE LAND SNAILS 
hausts the snail in its attempts to pass the barrier, for the 
more abundant the secretion, the greater the entangle- 
ment, and finally the snail dies from exhaustion. Protec- 
tions of this kind would be of no use in rainy weather, as 
the sand adheres together, and the snail can then pass 
over it very easily. 
Certain species of slugs (Fig. 13, Plate 1), that is, 
snails having no coiled shell, but alike in other respects, 
have the singular power of lowering themselves from some 
projecting point by means of this mucus, which they 
throw off from the posterior end of the creeping disk ; and 
we have seen a common slug (a species occurring abund- 
antly in our garden and fields), lower itself from the back 
of a high chair to the floor. They have no power, however, 
like the spider, to retrace their course. They will often 
hang suspended in mid air for sometime, apparel for 
no other purpose than to enjoy themselves. 
The snail has no power to leave its shell as many sup- 
pose. The shell is as much a part of the animal, as is the 
hard crust of a beetle a component part of the insect. And. 
not only this, the snail is attached to the shell by a per- 
manent muscular attachment, and cannot be withdrawn 
from it alive. In order to clean the shell of its contents, 
it is customary to scald it in boiling water, when the mus- 
cular attachment becomes separated from the shell, and 
the soft parts can be easily removed. The finding of 
empty shells in the woods, has oftentimes been cited as 
a proof that the snail can leave its shell, and the occur- 
rence of certain species of snails which have no visible 
shell, has served to strengthen a belief in this error. 
When the creature dies, the soft perishable parts are soon 
decomposed, or else devoured by insects, leaving the more 
enduring shell as a monument to its memory. On the ap- 
k i es E E ARS E E RENNE E eee 
i o i a a a aa ye Nn a EE 
