Limax rufus.
There are many species of the Slug; but they are not well defined, on account of the variable nature of their colour; the black and the brown kinds are, however, pretty well known: the black, in particular, is very destructive in kitchen-gardens, and commits great havoc in fields of cabbages and turnips.
In one or two species, the buckler, or smooth space near the head, contains a very small oval shell.
There is a very singular species of Slug found in Teneriffe, under stones in moist places, it is not more than an inch and a quarter in length; it is called Limax noctiluca, the night-shining Slug. The buckler, in this species, is very narrow, and covered with pores, which exude a kind of viscous substance, which has the property of shining with a phosphorescent light, like that of the glow-worm.
We may have some idea of the rapid increase of Slugs, by a fact mentioned by Dr. Leech, that two individuals of a small species have laid as many as seven hundred and sixty-six eggs; and these eggs were dried in an oven without destroying their vital powers, since, on being placed in a damp situation, they were afterwards hatched.
The following plan of taking and destroying Slugs was resorted to by a gentleman near Ipswich. Having heard that turnips were employed to entice Slugs from wheat, he caused a sufficient quantity to dress eight acres to be got together, and then, the tops being divided and the apples sliced, he directed the pieces to be laid separately, dressing two rows with them, and omitting two, alternately, till the whole field of eight acres was gone over. On the following morning, he employed two women to examine the tops and slices, and free them from the Slugs, which they threw into a measure: and when cleared, they were laid on those rows that had been omitted the day before. It was observed invariably, that in the rows dressed with the turnips, no Slugs were to be found upon the wheat, or crawling upon the land, though they abounded upon the turnips; while, on the undressed rows, they were to be seen in great numbers, both 011 the wheat and on the ground. The quantity of Slugs thus collected was nearly a bushel.
The Woodlike Bulla, ([Bulla lignaria].)
The animal of the Bulla is singular, from possessing-within its stomach three pieces of a substance resembling bone; these give that organ the power of crushing or grinding the food, forming a kind of gizzard. The bony portion of this stomach is represented in the foreground in the engraving. The Bulla lignaria is about two inches and a half in length, and is found in the European seas; Lamarck mentions as many as eleven species.