4. The =Stoat=, or =Ermine= (_Putorius erminea_). Body twelve inches, tail about three and a half inches long; slender; the body is scarcely broader than the head; tail longer than in the next species; summer fur, cinnamon brown above, white below; tail, cinnamon brown with black tip; winter fur quite white, but the end of the tail remains black. Mostly in fields, in the neighbourhood of plantations or woods; always abundant among sandhills, owing to the rabbits living there. The stoat usually follows its prey at night, stealing upon mice, rats, rabbits, hares, and song-birds; it is also sometimes very destructive in dove-cots and hen-houses. It must, however, be stated that the stoat is on the whole more useful than harmful. 5. The =Weasel= (_Putorius vulgaris_). Smaller than the stoat; head larger and thicker than the extremely slender, almost snake-like, trunk; legs short. The weasel is a very sharp little animal, and can easily pass along mouse-holes. Summer and winter coats alike—back brown, belly white. Its food chiefly consists of field-voles, also of rats and water-rats, young hares and rabbits, birds building near the ground, and also their eggs, which the weasel, by holding under its chin, manages to carry to its home; occasionally also lizards, blindworms, snakes, and frogs. The weasel does some damage in fowl-houses and dove-cots, and is also destructive to game. This, however, does not outweigh its very great use, since it is above all an untiring vole-catcher. When in any region the field-voles have multiplied excessively, an immigration of weasels takes place from surrounding parts. In years when there is a plague of voles the usual breeding time in spring is followed by another later on. A very large number of weasels may be found in a vole-infected district, and they thin out the mischievous rodents in a surprising manner. Nor are the weasels less useful in summer than in winter. They even follow under the snow the voles which winter in the country, and the slaughter effected at this period must exert a great influence on the following season, when these animals recommence their injurious work, and a pair of them that have survived the winter may perhaps produce two hundred others before the end of the summer. 6. The =Mink= (_Putorius lutreola_) is as large as a polecat, and may be regarded as a sort of link between it and the others. Leg and ears short; skin smooth-haired, brown both on the back and the belly; chin, lips, and a small patch on the neck, white; tail about one-third the length of the body. In well-watered regions on the banks of rivers, lakes, and ponds. Eats water-rats, water-birds, frogs, salamanders, fish, crayfish, water-insects, water-snails, and aquatic bivalves. Holstein, Mecklenburg, Pomerania, Brandenburg, Silesia.