22 
MUS DECUMANUS.— Pall. 
Brown or Norway Rat. 
PLATE LIV. Males, Female, and Young, Natural size. 
Mus, cauda longissima squamata, corpore setoso griseo, subtus albido. 
CHARACTERS. 
Grayish-brown above, dull white beneath, tail nearly as long as the body, 
feet not webbed ; of a dingy white colour. 
SYNONYMES. 
Mus Decumanus, Pallas, Glir,, p. 91-40. 
“ “ Schreber, Saugtbierc, p. 645. 
“ “ Linn., Syst. Nat. ed. Gmel., t. p. 127. 
Mus Aquaticus, Gesner’s Quadr., p. 732. 
Mus Decumanus, Shaw’s Genl. Zool., ii., p. 50 t. 130. 
Suemulat, Buff., Hist. Nat. viii., p. 206 t. 27. 
Mus Decumanus, Cuv., Regne Animal, 1, p. 197. 
“ “ Godman, vol. ii., p. 78. 
“ “ Dekay, p. 79. 
Mus Americakus, Dekay, American Black Rat, p. 81. 
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DESCRIPTION. 
Body, robust ; head, long ; muzzle, long, but less acute than that of the 
black rat ; eyes, large and prominent ; moustaches, long, reaching to the 
ears ; ears, rounded and nearly naked ; tail, generally a little shorter than 
the body, (although occasionally a specimen may be found where it is of 
equal length,) slightly covered with short rigid hairs. There are four toes 
on each of the fore-feet, with a scarcely visible rudimental thumb, protected 
by a small blunt nail ; live toes on each of the hind feet ; the feet are 
clothed with short adpressed hairs. The fur seldom lies smooth, and the 
animal has a rough and not an inviting appearance. 
COI.OUR. 
Outer surface of the incisors, reddish-brown ; moustaches, white and 
black ; the former colour preponderating ; the few short scattered hairs 
along the outer edges of the ear, yellowish brown ; eyes, black ; hair on 
