 ~ ARION INTERMEDIUS. 245 
Reproduction and Development.—'he congress of this interesting 
little species has never been described, but the eggs have been observed 
from August quite up to January ; they are oval in shape, and very large 
for the size of the animal, being two mill. long and one-and-half mill. 
broad or even of a larger size, gelatinous to the touch, semitransparent and 
pearly-white in colour, with opaline reflections. They have been observed 
to be deposited in irregular clusters strongly cemented together with a 
yellowish mucus, but not exceeding twenty in a cluster. 
The eggs hatch in about three weeks after deposition, the young when 
hatched may be, according to Dr. Scharff, light red, with violet tentacles, 
gradually changing however until by the time they have attained eight mill. 
in length they have become pale grey, a colour due to the viscera showing 
through the semitransparent skin, the head becomes also of a delicate grey, 
and no bands are perceptible on body or mantle. 
Mr. Gain, whose studies of the development, food, and habits of the 
slugs have been so complete and valuable, records that the young are 
usually dark green or yellow, and that the change in adult life is to a 
paler coloration. Some of the green variety, obtained early in April, only 
increased slightly in bulk during the following six weeks, but changed to 
a greenish yellow with a perceptible slaty-grey lateral band on each side; 
early in June they had increased materially in size, lost all trace of green, 
and were quite yellow, with well-marked lateral band, and dusky mid- 
dorsal line; they gradually became paler and almost white, except the sole 
and caudal gland, which were of a deeper colour, while the lateral and 
dorsal banding became fainter and more diffuse; towards the end of July 
the animals attained maturity and their final coloration, from which time 
onwards into January the adults and their egg-clusters have been found, 
but the animals do not appear to survive much beyond that period. 
Food and Habits. — Arion intermedius is described as naturally 
purely fungivorous, and in Germany is confined to the moss on pine- 
covered heathy land. In this country it is found chietly on the various 
species of Russula, Agaricus and Clavaria, but in captivity it is not nearly 
so restricted in its diet, eating lettuce freely, and also readily devouring 
cabbage, watercress, bread, and even paper. Breviére records that it feeds 
eagerly upon dead or moribund worms and small animals. 
It is not a garden species, nor does it usually frequent cultivated ground, 
but seems to prefer living in the open country, hiding beneath animal 
and other refuse, possibly on account of the fungoid growths thereon, 
they are also found in grass-fields where fungi abound, or on the margin 
of woods, concealed beneath dead leaves, close by the small fungi which 
grow in clusters at the foot of the trunks of old trees, and to which the 
animal approximates so closely in colour, that it has been likened to a 
small fungus just peeping above the ground. 
When at rest, the animal assumes the hemispherical shape, which is so 
characteristic of Arion ater, and in this position the remarkable crested 
tubercles of the body are most apparent. It is fond of burrowing in the 
earth, where it lies concealed during dry weather, and is also addicted to a 
peculiar habit of raising aloft the anterior part of its body and apparently 
looking around, like a stoat, a habit to which LZ. arborum is also addicted. 
In captivity, the skin soon becomes uniformly distended, and the 
rugosities effaced, but if kept in somewhat dry surroundings it very 
quickly becomes sickly and perishes, shrinking up especially posteriorly, 
but also showing a very peculiar constriction near the middle of the body. 
