The Rabbit begins breeding at six months old, and has several litters in each year. The young are usually from five to eight in number, sometimes even more; they are born blind and naked, and are produced in a separate burrow which the female digs for their reception, and lines with fur pulled from her own body. This brood-chamber has usually only a single entrance, and this the mother closes with earth after visiting and suckling her young family, which she is said to do only at night. When domesticated, the Rabbit, as is well known, differs materially from its wild state. It is larger, and its colours are usually white, black, brown, or fawn colour, sometimes alone, sometimes mixed in patches. Albinoes are common, and form a permanent race. The Angora Rabbit, which is usually albino, has the hairs very long; and the so-called “fancy Rabbits” have the ears more or less pendent at the sides of the head, and often so long as to touch the ground. A third British species is the MOUNTAIN HARE (_Lepus variabilis_), or Northern Hare, an inhabitant of all the northern parts of both hemispheres, which occurs in most parts of Scotland, and in Ireland, where, indeed, it takes the place of the common Hare. In its summer coat it is of a light fulvous grey colour, and is further distinguished from the common Hare by the shortness of the ears and tail, the former being shorter than the head, and the latter little more than half its length. In cold climates this animal becomes pure white in the winter. This Hare is absent from Central Europe, but reappears on the chain of the Alps. It will be unnecessary to enter into details with regard to the other species of this family, all of which more or less resemble those just described, both in appearance and habits. They are distributed over nearly the whole world except the Australian region, but they are most numerous in North America, where a great many species have been described, which are reduced by Mr. Allen to twelve. Four of these, however, present well-marked local races, which double the number of recognised permanent forms. FAMILY XVIII.--LAGOMYIDÆ (PIKAS).