Sewellel, a North American rodent of the genus aplodontia (Rich.), so called from the simple structure of the molars, apparently connecting the beaver with the squirrels through the spermophiles. It resembles the prairie dogs in the hairy and obtuse nose, fore feet with five claws, distinct ears, very short tail, and the flattened outline of the skull; but the rootless molars and the absence of post-orbital process bring it near the beaver. The fore claws are much larger than the hind ones, even the short thumb having one; the soles and heels naked; the mouth is rather small, the lips thick, and cheek pouches absent; the incisors are strong, flat, without grooves, and yellow, and the molars 5/4-5/4 prismatic, the anterior very small; the bony orbits very large, and the cranial cavity small; the descending branch of the lower jaw is twisted so as to be horizontal behind, and its lower angles are extended inward as far as the molars, the whole jaw being very strong. The only described species of the genus is the A. leporina (Rich.), about the size of a muskrat, with a short, thick, and heavy body; the color is reddish brown, grayish plumbeous below; the eyes are very small, the whiskers long and stiff, the ears rounded and covered with hair, and the tail much flattened; the fur is dense and soft, with longer bristly dark hairs interspersed; the limbs are short and robust; mammae six, the interior two between the fore legs; the length is 16 in., of which the head is 3 1/2 in. and the tail 1 1/2 in.
It is found on the N. W. coast, in Washington and Oregon territories, and in California, in timber lands near the coast. They form small societies, living in burrows, and feeding on vegetables; the natives make robes of the skins.
Sewellel (Aplodontia leporina).