189 



GENUS MUS.— Linn. 

 Incisive 5-; Canine jpqj ; Molar ^^ = 16. 



Cheek-teeth, furnished with tubercles ; ears, oblong or round, nearly 

 naked ; without cheek-pouches ; fore-feet, with four toes and a wart, 

 covered with an obtuse nail, in place of a thumb ; hind-feet, pendac- 

 tylous ; tail, long, usually naked and scaly ; fur, with a few long, 

 scattered hairs, extending beyond the rest. 



The generic name Mus is derived from the Latin mus, a mouse, from 

 the Greek r^vs, (mus,) a mouse. 



There are upwards of two hundred species of this genus described as 

 existing in various quarters of the globe, of which about nine well-deter- 

 mined species are found in North America, three of which have been in- 

 troduced. 



MUS RATTUS.— Linn. 

 Black Rat. 



PLATE XXIII. — Old and Young, of various Coloues. Natural size. 



M. Cauda corpore longiore ; pedibus anterioribus ungue pro pollice in- 

 structis ; corpore atro, subtus cinereo. 



CHARACTERS. 



Tail, longer than the body ; fore-feet, with a claw in place of a thumb, 

 hluisli-blach above, dark ash-coloured beneath. 



SYNONYMES. 



Mus Rattus, Linn., 12th ed., p. 83. 



" " Schreber, Saugetliiere, p. 647. 



" " Desmar., in Nouv. Diet., 29, p. 48. 



Rat, Buffon, Hist. Nat., vol. vii., p. 278, t. 36. 

 Rat Ordinaire, Cuv., Regne Anim., p. 197. 

 Black Rat, Penn., Arc. Zool., vol. i., p. 129. 

 Roller Pontopp., Dan. i., p. 611. 



