SLUGS. 
69 
and the internal shell claw-shaped. In Testacella 
we have a near approach to the snails, and 
through Vitrina is connected with them; the 
shell is small, ear-shaped, placed externally at 
the hinder extremity of the body, and covers the 
mantle, beneath which, on the right side, is the 
respiratory orifice. 
Genus Arion. 
Arion was a horse remarkable for its speed, 
but our Arion is remarkably slow. 
Arion ater —(the Blach Slug ) (PI. V., fig. 31)—- 
is familiar to all as a common object of our gar¬ 
dens and waysides, and is also too well known to 
the gardener, as being more or less injurious to 
the early cabbages and other garden produce; 
and in the autumn as one among other mollusks 
that mutilate and render repulsive the fruits of 
that season. Dead animal matter—even that 
of their own species—does not come amiss to 
them; they also feed on the common earths 
worm. 
The adult animal is usually brownish or 
greyish-black; at other times brown or red¬ 
dish; the young individuals are grey, whitish, 
bluish-white, or yellow-coloured. It attains a 
length of from three to five inches. The shell 
is composed of loosely aggregated calcareous 
particles. 
