Fur grayish-black above; ash-colour beneath : tail a little longer than the body.
M. Rattus, Desm. Mammal, p. 300. Mem. Brit. An. p. 20. Black Rat, Penn. Brit. Zool. vol. I. p. 113. Shaw, Gen. Zool. vol. II. p. 52. pi. 130.
Length of the head and body seven inches four lines; of the head one inch ten lines; of the ears eleven lines and a half; of the tail seven inches eleven lines.
Head long; muzzle sharp-pointed ; lower jaw very short; eyes large and prominent; ears oval, broad, and naked: whiskers long : fore feet with four toes, and a claw in the place of a thumb; hind feet with five: tail longer than the body, almost entirely naked, and covered with small scales disposed in rings. Colour of the upper parts deep iron-gray, or grayish black; those beneath dull ash-colour: feet and tail dusky.
Frequents houses, and is truly indigenous; but is now much less general than the next species. Food various. Breeds frequently in the year, producing from six to eleven at a time.