MAMMALIA. 31 



strong and offensive odour which proceeds from the buck. It is quite indescrib- 

 able : several times, whilst skinning the specimen, which is now mounted at the 

 Zoological Museum, I was almost overcome by nausea. I tied up the skin in a 

 silk pocket-handkerchief, and so carried it home : this handkerchief, after being 

 well washed, I continually used, and it was, of course, as repeatedly washed ; yet 

 every time, when first unfolded, for a space of one year and seven months, I dis- 

 tinctly perceived the odour. This appears an astonishing instance of the perma- 

 nence of some matter, which in its nature, nevertheless, must be most subtile and 

 volatile. Frequently, when passing at the distance of half a mile to leeward of a 

 herd, I have perceived the whole air tainted with the effluvium. I believe the 

 smell from the buck is most powerful at the period when its horns are perfect, or 

 free from the hairy skin. When in this state the meat is, of course, quite 

 uneatable ; but the Spaniards assert, that if buried for some time in fresh 

 earth, the taint is removed. These deer generally weigh about sixty or seventy 

 pounds." — D. 



Family — MURID^E. 



1. MUS DECUMANUS. 

 Mus decumanus, Auctorum. 



In the extensive collection of Rodent animals brought home by Mr. Darwin, 

 I find several specimens of the above named species, that is to say, animals which 

 resemble the European specimens of Mus Decumanus in all those characters which 

 are the least liable to variation in individuals of the same species, such as the 

 proportions which the various parts of the animal bear to each other : they 

 differ, however, somewhat in colouring. 



Buenos Ayres, Maldonado, Valparaiso, East Falkland Island, and Keeling 

 Island, are each, it appears, infested with the common European rat. I have 

 now before me two specimens from East Falkland Island, and one specimen 

 from each of the other localities, and among these I find none equal in size to the 

 largest European specimens : as regards the colouring, the Buenos Ayres speci- 

 men differs only from the English specimens of Mus Decumanus, in having the 

 upper parts of a richer and deeper hue, owing to the tips of the shorter hairs being 

 of a deep yellow instead of pale yellow, and in having a rusty tint over the 

 haunches. 



