50 SNAILS AND SLUGS, CONSIDERED 



fortunately, it is hot often met with, as the damage inflicted by 

 it on pot-plants is tenfold greater than that caused by the common 

 worm. 



Snails and Slugs, considered with reference to Horticulture. 



The only snail which interests the gardener is the Helix aspersa of 

 naturalists ; for that which they have named the garden snail (H. 

 hortensis) is rather a field than a garden species. The former is much 

 the larger of the two, and has a dull shell marked with three faint 

 mottled brownish bands, and a white rim round the aperture ; while 

 the shell of the latter is glossy, distinctly banded with vivid colours, 

 and the oral rim is brown. 



The slugs which frequent the garden are the Lirnax agrestis, L. 

 cinereus, and L. ater. The L. agrestis, the commonest, is of a greyish 

 colour, and from one to two inches long ; the L. cinereus is, on the 

 contrary, from three to five inches in length, of a greyish or dusky 

 colour, with darker spots and stripes ; and the L. ater is easily known 

 by the jet black and wrinkled skin of its back. 



Both snails and slugs are furnished with tentacula placed in front of 

 the head, and which, by a singular process, can be drawn entirely 

 within it. The mouth is armed above with a semi-lunar horny jaw, 

 having its outer or cutting edge furnished with one or several serratures. 

 On the right side or neck of the snail and slug there are three aper- 

 tiires, that nearest the head being the respiratory orifice, the next the 

 anus, and the third the exit for the organs of generation. Snails and 

 slugs crawl on the flat sole which constitutes their foot and belly, and 

 which is very muscular ; but progression is principally performed by a 

 pair of muscles which extend from the tail to the fore part of the belly, 

 running along the middle of the foot. 



Snails and slugs are hermaphrodite and oviparous. They deposit 

 their eggs under clods of earth, loose stones, or in the ground, in which 

 the parent digs, with its foot, a circular hole about an inch deep. The 

 eggs vary from twelve to thirty in number ; they are white, oval or 

 round, about the size of a common shot, with a smooth soft skin, which 

 is entirely membranous in the slug, but in the snail contains innume- 

 rable minute calcareous grains, always in a crystalline state, and 

 usually of a rhomboid figure. They are, in ordinary seasons, hatched 

 in about three weeks after being laid ; but the time is regulated much 

 by temperature, so that in cold seasons it is greatly retarded. The 

 young issue from the egg in the likeness of their parents, active and 

 furnished with every organ ; and the young snails have even then a 

 shell fitting their size and strength. The length of life of the snail 

 or slug cannot be determined. The shell of the snail is usually com- 

 pleted before the termination of the second year, when the animal may 

 have been said to have reached maturity. The snail and the slug are 

 very patient of injury, often recovering from severe wounds ; repairing 

 their broken shells, and reproducing such parts of their bodies, pos- 

 terior to the neck, as may have been cut away. In winter, snails and 

 slugs retire under stones, clods, or into the crevices of walls : the slugs 



