SLUGS AND SNAILS 305 



closing up the mouth of the shell with a lid of slime and limy matter, which 

 sets hard but remains porous. 



Slugs are popularly supposed to be snails that have lost or not grown any 

 shells ; but this is not exactly true. In some species for example, the Yellow 

 Cellar Slug (Limax flavus) and the large grey species, with black spots, known 

 as Limax maximus there is a small shell under the skin. The Large Black 

 Slug (Arion ater) has certain calcareous crystals in the same part of its body, 

 and Testacdla has a tiny visible shell, like a skullcap, on the hinder end of its 

 body. 



Slugs are more active than snails. It has been calculated that a slug would 

 travel a mile in eight days, whilst a snail would take a fortnight to do so. 



The British slugs form two classes (Arionida and Limacidce), the largest 

 and commonest being the Black Slug (Arion ater), which feeds not only on 

 vegetable food but also on flesh, the excrement of other creatures, and even 

 its own kith and kin. The young are yellowish white in colour. 



Together with Arion minimus, this slug possesses the power of contracting 

 its body into a round lump when alarmed. A. minimus has bands of colour 

 on its sides which distinguish it from A . ater. 



The Cellar Slugs (Limax maximus and L. flavus} are frequently found in 

 cellars, it is true, but they also inhabit many other places. The former is 

 usually grey, the latter yellow, with blue tentacles. The Tree Slug (L. arborum 

 or marginatus] can lower itself from a branch to the ground by a cord of slime, 

 and return by the same means. Altogether, we have nineteen species in the 

 British islands. 



To return to the snails, sufficient has been said about the Common Garden 

 Snail ; but there are many other species in these islands, some seventy in 

 all, twenty-two belonging to the genus Helix. Others are very small, requir- 

 ing a pocket lens to see them well : among these we may mention the 

 BEAUTIFUL SNAIL (H. pulchella), the ROCK SNAIL, the PRICKLY SNAIL, the 

 PLATED SNAIL, etc. 



The Edible Snail (H. pomatia), sometimes called the ROMAN SNAIL, because 

 it is said to have been introduced by the Romans, is the largest of all, and 

 found still in certain parts of the country Kent, Surrey, and Hants. The 

 Common Snail also is eaten as a delicacy in some country districts, especially 

 in the North. 



The Striped Snail (H. nemoralis] is smaller than H. aspersa, and of red or 

 yellow colour, striped with one to five spiral brown bands. This varies very 

 much both in banding and colour. The rim or lip of the shell is dark brown ; 

 in H. hortensis, which is otherwise very similar, it is white. 



The Hairy Snail (H. hispida) is a small brown species found in hedges, 

 with minute hairs on the shell. 



H . virgata, about \ inch in diameter, abounds on chalky downs near the sea. 

 White, with one or more brown bands. 



Hyalina crystallina is a member of a genus of small snails with smooth, 



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