16 A MANUAL OF AMERICAN LAND SHELLS. 



All the species are extremely voracious, and devour au incredible 

 quantity of food in a short time. Those found in this country are gen- 

 erally supposed to be vegetable feeders, but nearly all of them subsist 

 occasionally upon dead animal matter, of which they seem to be fond, 

 and when in confinement sometimes attack and devour each other ; and 

 the foreign genus Testacella, is known to prey habitually upon earth- 

 worms. It is probable, therefore, that in their natural condition all of 

 them at times resort to animal food and devour earth-worms, insects 

 and their larvte, and such other animals as, inhabiting the same retreats, 

 are like themselves slow of motion and defenseless. It is certain, how- 

 ever, that the principal food of those species which frequent the neigh- 

 borhood of houses and gardens consists of the tender leaves of succu- 

 lent plants and of ripe fruits. Upon these, in Europe, they perpetrate 

 serious ravages, often destroying in a night the labors and hopes of the 

 gardener, and in some years committing so much injury and interfering 

 to such a degree with the prosperity of the agriculturist that they are 

 ranked among the scourges of the country. Like caterpillars, locusts, 

 and rats, they are considered to be perpetual enemies, and a war of ex- 

 termination is carried on against them. To limit the extent of the evil, 

 many remedies have been i^roposed, and among others the prayers and 

 exorcisms of the Church have been claimed, but without any consider- 

 able abatement of it. Happily, we are not in this country subject, in 

 the same degree, to the mischief done by these animals, for their excess- 

 ive increase is kept in check, probably, by the vicissitudes of the cli- 

 mate; but it may be useful to know that a border of ashes, sand, or saw- 

 dust, laid around the bed containing the plants it is desired to i)rotect, 

 will i)rove an impassable barrier to the slugs, so long as these substances 

 remain dry. When the slugs attempt to pass the barrier, they become 

 entangled in the dry ashes or sand, which envelopes them entirely. 

 The particles of these adhere to the viscid surface of the animals, which, 

 in vain endeavoring to disengage themselves from them by secreting 

 new mucus, at length become exhausted and die. 



Their growth is remarkably rapid. The young have been known to 

 double their size and weight in a week. The earliest hatched young of 

 the season generally attain their full maturity before the end of the first 

 year, although they may afterwards increase somewhat in bulk. Those 

 which leave the egg at a later period, mature during the second year. 

 Individuals kept in confinement and fully fed, reach a much greater size 

 than when in their natural condition. 



