304 THE SCHOOL GARDEN. 



Snails and Slugs. The garden snail is a familiar sight, 

 sometimes occurring in very large numbers. This species 

 (Helix aspersa) has a somewhat rough brownish shell, 

 which to be seen to advantage should be washed and 

 examined wet. The snail itself is over two inches long, 

 being the largest to be met with in gardens in this country. 

 Snails are vegetarian in habit, and when numerous may be 

 very destructive. They hibernate in companies, closing 

 the mouth of their shells with a dried mucus-like secretion. 

 Some snails form a porous limy plate, like the shell of an 

 egg, which they use for this purpose. 



Snails make interesting objects of study, and some 

 should be kept under observation in school. They are 

 very hardy and live quite well in captivity. They may be 

 kept in a box and fed with ordinary vegetables or weeds, 

 e.g. lettuce, cabbage, dandelion, etc. The atmosphere of 

 the box should not be allowed to become too dry. 



For a practical study of a snail see p. 150. 



Amongst slugs, the most familiar in gardens is the grey 

 field slug (Limax agrestis), about four-fifths of an inch long, 

 which should be compared with the snail as regards struc- 

 ture. Slugs have no spiral shell, but most have, embedded 

 in the oval patch known as the mantle, just behind the 

 head, a thin plate-like structure or detached limy granules. 

 The breathing opening of a Limax is situated in a notch of 

 this area at its posterior right side. Another slug some- 

 times found in gardens, although oftener about ditches or 

 in damp woods, is the fine large black slug (Arion ater). 



Slugs are fond of damp, they lie concealed during the 

 day, coming out at night to feed ; they are frequently to 

 be seen, however, after a shower of rain, if the weather is 

 mild, during the day. 



Slugs are mostly injurious animals in the garden, the 

 greatest amount of harm being done in wet seasons. There 

 is one type, known as Testacella, which is carnivorous, 

 feeding on worms and insect larvae in the soil, which on 

 the whole may be looked upon as beneficial. Testacella is 

 readily recognised by the cap-like shell it carries at the 

 posterior tip of the body. 



