mites; but they seem never to be at rest, moving with the greatest rapidity. A striking feature in the history of the little animal is that it appears to take up its abode within the interior of the slug; effecting an entry by means of the respiratory aperture, and coming forth occasionally to ramble over the surface of the body. The slug does not appear to suffer any inconvenience from these parasites, and even allows them to run in and out of the lateral orifice without betraying the slightest symptoms of irritation. Arion ater has a wide geographical range. ARION HORTENSIS (the Garden Arion Slug) (Pl. V., fig. 29)-differs from the last species; it is much smaller and more slender, and is provided with grey longitudinal stripes. The foot is bordered with orange. The imperfect shell is more compact than that of A. ater. The horny jaw (fig. 11) is arched, strongly ribbed, and its margin crenulated; it contrasts strongly with the smooth rostrated jaw of Limax (see fig. 12). Fig. 11.-Jaw of A. hortensis. Like the last species, it is common in woods, damp hedges, and gardens. The eggs of this species are said to be phosphorescent for the first fifteen days after they have been laid. GENUS LIMAX (Limax, a slug). The Limaces differ little from the Arions, but are destitute of a mucous pore at the end of the tail; the mantle is concentrically marked and not granulated, and the respiratory aperture near the hind part of its border; the tail is carinated, or ridged. Fig. 12.-Jaw of The horny jaw of Limax (fig. 12) is strongly arched, smooth and rostrated in front; it differs markedly from that of Arion, and resembles that of L. gagates. Helicella (fig. 18) and Vitrina. The species feed chiefly on tender herbage, fruits, and vegetable substances in general; they are very voracious, feeding after rain, or in the evening to early morn; during the heat of the day they remain concealed, and during droughts and frosts they are torpid, buried underground. They are the great pests of our gardens and cultivated lands,-to young oats, peas, tares, clover, and turnips, they give preference; and many fields have been made barren by them, and have had to be ploughed down and resown. Although vegetables are the legitimate food of the slug, most of them are occasionally carnivorous, not from necessity, but from pure and decisive choice; some of them may be even convicted of cannibalism. They have, however, numerous enemies, especially among birds: the principal of these are the blackbird and thrush, whose notes Nice finger'd Art must emulate in vain. Ducks and geese are very partial to slugs. The Limaces when irritated withdraw their heads beneath the mantle; this attitude is also assumed during repose. LIMAX MAXIMUS (Pl. V., fig. 32), so called from its being the largest of the slugs, attains the length of five or six inches. This large grey slug is spotted and striped with black. The shell is thin, flat, oblong, about six lines long and four broad. The dental formula is 90-1-90 160 • This species is widely distributed, is a frequent visitor to our pantries and cellars, lurking in damp corners, or remaining concealed in the dust-bins, or other sheltered situations, during the day; foraging during the night, its perambulations are rendered distinctly visible by its trail, for the thick glutinous slime which is copiously exuded becomes very iridescent when dry. It is very omnivorous, preferring certainly, as indicated by its attachment to the dwellings of man, the refuse from our kitchens and the delicacies of our tables when within its reach. It is, however, frequent in moist woods, hybernating in the mossy crevices of trees, or in |