10 LAND AND FRESH-WATER SHELLS OF N. A. [PART I. 



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 defenceless. It 

 is certain, however, that the principal food of those species which 

 frequent the neighborhood of houses and gardens, consists of the 

 tender leaves of succulent 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 proposed, and among others 

 the prayers and exorcisms of the church have been claimed, but 

 without any considerable abatement of it. Happily, we are not 

 in this country subject, in the same degree, to the mischief done 

 by these animals, for their excessive increase is kept in check, 

 probably, by the vicissitudes of the climate ; but it may be useful 

 to know that a border of ashes, sand, or sawdust, laid around the 

 bed containing the plants it is desired to protect, will prove an 

 impassable barrier to the slugs, so long as these substances 

 remain dry. When the slugs attempt to pass the barriei', they 

 become entangled in the dry ashes or sand, which envelops them 

 entirely. The particles of these adhere to the viscid surface of 

 the animals, who, in vain endeavoring to disengage themselves 

 from them by secreting new mucus, at length become exhausted 

 and die. 



Their growth is remarkably rapid. We have known the young 

 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 eg% 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. 



They possess, in a remarkable degree, the power of elongation 

 and contraction of the body. When fully extended it is long, 

 narrow, more or less cylindrical, and generally terminating in a 

 sharp point. The carina of the carinated species disappears. 



