RODENTIA. MURIDiE. 63 



Observations. This animal is not a native of this country, but 

 is supposed to have been introduced. Though a beautiful little 

 animal, still it is not regarded with much favor ; the unpleasant 

 odor produced where it resides, serving to produce a strong prej- 

 udice and disgust. 



2. Mus rattus. Lin. Black Rat. 



Mus domesticus major, Ray. 



Black Rat, Pennant, Zool., i. p. 113. Harlan, Fauna Am., p. 148. God- 

 man, Nat. Hist., ii. p. 83. 



Specific characters. Grayish-black above, ash beneath ; ears 

 half the length of the head ; tail longer than the body. 



Description. Head elongated ; muzzle tapering ; mystachial 

 bristles numerous ; upper jaw projects beyond the lower, which 

 is remarkably short ; tongue smooth ; ears rounded, simple, 

 naked, and half as long as the head ; eyes large and projecting, 

 though not remarkably so ; feet plantigrade ; five toes on each 

 foot, concealed in the skin, excepting the terminal joint and 

 claw ; tail longer than the body, almost destitute of hair, but 

 covered with rings of scales ; color of the upper parts grayish- 

 black ; of the lower, dull ash ; feet and tail dusky. 



Observations. The Black Rat is supposed by many to have 

 been introduced into this country from Europe. Others, how- 

 ever, are undecided as it regards this question. It was once more 

 numerous than it is at present. This animal I found quite numer- 

 ous a few years since about an old mill in Williamstown, which is 

 the only place in which I have met with it. It is supposed to 

 have been extirpated, or driven away from its former residences 

 by the Brown or Norway Rat. 



3. Mus decumanus. Pallas. Brown Rat. 



Mus Norwegicus, Brisson, Reg. An., p. 173. Erxl., Syst., p. 381. 



Norway Rat, Pennant, Brit. Zool., i. p. 115. 



The Common, Brown, or Norway Rat, Godman, Nat. Hist., ii. p. 78. 



Specific characters. Color of the upper parts grayish-brown, 

 w r ith a tawny tint ; dirty white beneath ; ears and muzzle nearly 



