£34 INTRODUCTION. 
upon them. We have frequently noticed that when 
in a state of confinement, Helix concava, itself not an 
abundant species, will generally destroy other species 
which are kept with it ; and the animal of GlanJLna 
truneata, which we have occasionally had in captivity, 
has imiformly destroyed those of the other genera and 
species placed within its reach. In the same manner 
IAmax variegatus, when kept a few days without food, 
has devoured the weaker Limax ctgrestis, leaving no 
vestige of them except the rudimentary shell. A\*e have 
also been informed, on what we consider to be good au- 
thority, that a foreign species, believed to be Helix 
nemoralis, which existed formerly in great numbers in 
Charleston, S. C, was completely exterminated by Buli- 
mus decollatus, a foreign species also, which now flour- 
ishes there in abundance. In this case, however, the 
destruction of the one species, though subsequent to the 
introduction of the other, might not have had any con- 
nection with it. Birds also make great havoc among 
them, where the woods are so far opened as to permit 
the entrance of such of them as do not usually fre- 
quent the forest. They seize the shell with their beaks, 
and bearing it to a prostrate tree or log, break it with 
repeated blows of the point of the bill, and extract the 
soft animal. It is not uncommon to find numerous 
broken shells about a spot in the woods which has been 
selected by the bird as the seat of its operations. The 
little heaps of shells in the woods are by some supposed 
to be due to the agency of squirrels, and not of birds, 
