=Food of Land and Fresh-water Mollusca.=--_Arion ater_, the great black slug, although normally frugivorous, is unquestionably carnivorous as well, feeding on all sorts of animal matter, whether decaying, freshly killed, or even in a living state. It is frequently noticed feeding on earthworms; kept in captivity, it will eat raw beef; it does not disdain the carcases of its own dead brethren. An old man near Berwick-on-Tweed, going out one morning to mow grass, found a black slug devouring, as he supposed, a dead mouse. Being of an inquisitive turn, and wishing to ascertain if it were really thus engaged, he drew the mouse a little back. When he returned in the evening, the mouse was reduced almost to a skeleton, and the slug was still there.[47] Indeed it would seem almost difficult to name anything which _Arion ater_ will not eat. Dr. Gray mentions[48] a case of a specimen which devoured sand recently taken from the beach, which contained just enough animal matter to render it luminous when trodden on in the dark; after a little time the faeces of the slug were composed of pure sand, united together by a little mucus. A specimen kept two days in captivity was turned out on a newspaper, and commenced at once to devour it. The same specimen ate dead bodies of five other species of slugs, a dead _Unio_, pupae of _Adimonia tanaceti_, part of the abdomen of a dragon-fly, and Pears’ soap, the latter reluctantly.[49] According to Simroth[50] and Scharff[51] the food of several of our British slugs, _e.g._ _Limax maximus_, _L. flavus_, _Arion subfuscus_, _A. intermedius_, consists of non-chlorophyllaceous substances only, while anything containing chlorophyll is as a rule refused. On the other hand _L. agrestis_ and _Amalia carinata_ feed almost entirely on green food, and are most destructive in gardens. The latter species lives several inches under ground during the day, and comes to the surface only at night. It is largely responsible for the disappearance of bulbs, to which it is extremely partial. _L. marginatus_ (= _arborum_ Bouch.) feeds exclusively on lichens, and in captivity absolutely refuses green leaves and a flesh diet. It follows therefore, if these observations are correct, that the popular notions about slugs must be revised, and that while we continue to exterminate from our gardens those species which have a taste for chlorophyll, we ought to spare, if not encourage those whose tastes lie in the opposite direction.