THE SLUG 



211 



summer, and autumn under wet decaying pieces of wood, 



under stones or fruit, in the grass, on tlie sliady side of fences ; 



in a word, in moist, dark situations. They esjieciall.v shun 



sand, ashes, and sawdust, because these substances tend to 



dry up the mucus which they 



secrete over their body to retain 



its internal fluids. Slugs are 



nocturnal (Fig. 162), hence they 



have the reputation of being 



rather rare. During the winter 



they live in the ground, encased 



in their own slime, liut some 



species frequent greenhouses in 



cold weather and in consequence 



of this habit may remain active 



all the year round. 



The food of slugs consists 

 chiefly of the green leaves of suc- 

 culent plants, and also of ripe 

 fruit, such as aijples. Our larg- 

 est slug, Limaxmaxinms,'^ in esisily 

 maintained in captivity l^y keep- 

 ing in a dark box and feeding on 

 the blanched leaves of caljbage. 

 In captivity one individual will sometimes devour another. 



Economically, slugs are of importance because at times in some 

 localities they cause much destruction in gardens and greenhouses. 

 Particularly in Europe, a species of Limax has often devastated 

 fields of young shoots and devoured many bulbous plants. 



In the apparent absence of a shell the slug seems to be an 



^ Largest. 



Fig. 197. — lUustriiting the transi- 

 tion of form in the shell of certain 

 Opisthobranchs, from the pointed 

 spiral to the almost flat plate. The 

 genera figured are : A, Actipon ; 

 B, Aplustrum ; C, Cyliehna ; D, 

 Atys; E. Philine ; F, Dolabella ; 

 G. .\plysia ; H. Pleurobranchus. 

 Drawn to various scales. From 

 C'ooke, " MoUusca." 



