“They always work during the night, and have been known during a single night to have accumulated as much mud as amounted to some thousands of their little handfuls. Every fall they cover the outsides of their houses with fresh mud, and as late in the autumn as possible, even when the frost has set in, as by this means it soon becomes frozen as hard as a stone, and prevents their most formidable enemy, the Wolverine, or Glutton, from disturbing them during the winter. In laying on this coat of mud, they do not make use of their broad flat tails, as has been asserted—a mistake which has arisen from their habit of giving a flap with the tail when plunging from the outside of the house into the water, and when they are startled, as well as at other times. The houses, when completed, are dome-shaped, with walls several feet thick.” THE PORCUPINE FAMILY. [Illustration: PORCUPINES.] The Porcupines are singular animals, endowed with a very peculiar faculty, that of causing their body, which is covered with quills, to bristle up, and thus forming for themselves a formidable armor. The small family of Porcupines is divided into four genera—Porcupines proper, the Brush-Tailed Porcupine, the Canadian Porcupine and the Prehensile Porcupines. COMMON PORCUPINES. The species often called the Crested Porcupine, inhabits Italy, Greece, Spain, Northern Africa, and different parts of Asia. We shall describe it, which will serve to characterize the whole genus. This Porcupine is one of the largest Rodents; its average length exceeds twenty-four inches. The principal features are very powerful upper incisors, short thick toes, furnished with strong claws, a large head, small eyes, short ears, a slightly split mouth, and thick-set shape, combined with an awkward and clumsy gait. The body of this animal is covered with pointed quills from eight to nine inches long. By means of the action of an enormous muscle, which moves at the will of the animal, these can bristle up and radiate in all directions. The tail is rudimentary, and is not, like the back, covered with quills, but with entirely hollow, white tubes, which produce a sharp sound when they clash together. The muzzle is furnished with long and strong whiskers; the head and neck are covered with flexible hair, which is not prickly, but is susceptible of standing on end.