| mountain beaver | (n) bulky nocturnal burrowing rodent of uplands of the Pacific coast of North America; the most primitive living rodent, Syn. sewellel, Aplodontia rufa |
| Sewellel | n. [ Of American Indian origin. ] (Zool.) A peculiar gregarious burrowing rodent (Haplodon rufus), native of the coast region of the Northwestern United States. It somewhat resembles a muskrat or marmot, but has only a rudimentary tail. Its head is broad, its eyes are small and its fur is brownish above, gray beneath. It constitutes the family |