The Sewellel Family, (_Aplodontidae_), contains five or six species and is of unusual scientific interest. The Sewellel, Mountain Beaver, Farmer or “Showt’l” (_Aplodontia rufus_ and _major_), is an animal of the size and general appearance of a large, short-tailed muskrat. It inhabits a few localities in remote regions in the mountain-valleys of northern California, Oregon, Washington, and southern British Columbia. It feeds like a beaver, climbs bushes four feet high, burrows in _wet_ ground, and fights like a little fiend when brought to bay. Notwithstanding the size of this animal, it is very seldom seen, and is but little known. The Squirrel Family, (_Sciuridae_), is large (one hundred and forty-one species), very interesting, and entitled to much consideration. In the present enclosure will be shown in summer many species of interesting ground squirrels, chipmunks, and marmots. In winter all the squirrels, save one or two hardy native species, will be found in the Small-Mammal House, near by. The Rabbit Family, (_Leporidae_), is one of the most difficult to install and exhibit. Its members are large and showy, but for several reasons it is very difficult to keep them on exhibition in captivity. In time, however, all four of the great groups—Rabbit, Varying Hare, Jack Hare, and also the Pikas, forming the allied Family _Ochotonidae_—will be represented by specimens. Just what can be accomplished satisfactorily with the most interesting members of the Jumping Mouse, Pouched Rat, and Pocket Gopher Families, remains to be determined by trial. If they can be induced to show themselves to visitors, during daylight hours, they will be kept for exhibition; otherwise not. At present, some examples of these species can be seen in the Reptile House. In Winter.—In the temperate zone, when “winter comes to rule the varied year,” all the burrowing animals must retire to their burrows, live upon their buried stores of winter food, and hibernate until spring. The tropical species do not know how to hibernate, and therefore they must be taken indoors, or they perish. In order that our native species of rodents may be seen all winter, and that the tropical species may be kept alive, nearly all the animals that in summer live in the Burrowing Mammal Quarters are removed in autumn to the well-warmed Small-Mammal House. It also happens that in summer a few of the small carnivores, and all armadilloes, are kept in these Quarters. In addition to the rodents which it is practicable to exhibit in these enclosures, the summer season will find some of them occupied by certain especially interesting species which need the soil of Mother Earth as well as sunlight and air. Here will be found the Armadilloes, the Nasuas, the Raccoon Dogs, the Swift Foxes and a few others, which in winter belong in the Small-Mammal House. THE PRAIRIE-DOG VILLAGE, No. 41.