122 The Official Guide to the 
first family is that of eer. or the. Slugs, 
sufficiently we!l-known objects, and one of the best 
known, at least in the flesh, is the Great Black 
Slug (Arion ater), although, in consequence of 
the shell with which these creatures are generally 
provided, being in this species reduced to merely 
a number of loose calcareous grains, covered by 
the hinder part of the shield, it is not sufficiently 
substantial for its remains to find a place in this 
collection. It is, nevertheless, a very interesting 
animal, and possessed of pecularities which do 
not exist in the other genera. There is a second 
species, A. Hortensis, much smaller, of an orange 
colour, and possessing a slightly more compact 
shell. Both species are common in woods and 
damp places, hiding under stones and logs, and 
coming abroad after rain or in the dewy evening, 
feeding on almost any decaying substance, animal or 
vegetable. 
Of the genus Lzmax, containing the chief pests. 
of our gardens and cultivated lands, may be men- 
tioned ZL. flavus, a great yellow slug, whose slimy 
tracks may so frequently be seen in cellars and damp 
buildings, where it prowls at night in search of 
kitchen refuse ; ZL. maximus, a giant, five or six inches 
long, intruding itself almost everywhere; and JZ. 
agrestis, our common garden pest. All these possess 
a fairly-developed shell, to be found situated under 
the shield. One species, ZL. arborum, possesses 
the power of letting itself down to the ground by 
forming a thread from its own slime, up which it can 
again climb should it desire to do so. ‘This power is 
possessed, in a less degree, by some of the other 
species of this genus. 
Testacella haliotidea, is a remarkable species, the 
only member of the genus found in this country ; and 
