6o A LARGE RODENT. [chap, ii 



perceived the odour. This appears an astonishing instanc 

 of the permanence of some matter, which nevertheless in i^ 

 nature must be most subtile and volatile. FrequentlyT 

 when passing at the distance of half a mile to leeward of 

 a herd, I have perceived the whole air tainted with 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 Gauchos assert, that if buried for some 

 time in fresh earth the taint is removed. I have somewhere 

 read that the islanders in the north of Scotland treat the 

 rank carcasses of the fish-eating birds in the same manner. 



The order Rodentia is here very numerous in species : 

 of mice alone I obtained no less than eight kinds.* The 

 largest gnawing animal in the world, the HydrochcBrus 

 capyhara (the water - hog), is here also common. One 

 which I shot at Monte Video weighed ninety-eight pounds : 

 its length, from the end of the snout to the stump-like 

 tail, was three feet two inches ; and its girth three feet 

 eight. These great Rodents occasionally frequent the 

 islands in the mouth of the Plata, where the water is 

 quite salt, but are far more abundant on the borders of 

 fresh-water lakes and rivers. Near Maldonado three or 

 four generally live together. In the daytime they either 

 lie among the aquatic plants, or openly feed on the turf 

 plain, t When viewed at a distance, from their manner 

 of walking and colour they resemble pigs ; but when 

 seated on their haunches, and attentively watching any 

 object with one eye, they reassume the appearance of their 

 congeners, cavies and rabbits. Both the front and side 

 view of their head has quite a ludicrous aspect, from the 

 great depth of their jaw. These animals, at Maldonado, 

 were very tame ; by cautiously walking, I approached 

 within three yards of four old ones. This tameness may 



* In South America I collected altogether twenty -seven species of mice; 

 and thirteen more are known from the works of Azara and other authors. 

 Those collected by myself have been named and described by Mr. Water- 

 house at the meetings of the Zoological Society. I must be allowed to take 

 this opportunity of returning my cordial thanks to Mr. Waterhouse, and to 

 the other gentlemen attached to that Society, for their kind and most liberal 

 assistance on all occasions. 



t In the stomach and duodenum of a capybara which I opened, I found a 

 very large quantity of a thin yellowish fluid, in which scarcely a fibre could 

 be distinguished. Mr. Owen informs me that a part of the oesophagus is so 

 constructed that nothing much larger than a crowquill can be passed down. 

 Certainly the broad teeth and strong jaws of this animal are well fitted to 

 g'rind into pulp the aquatic plants on which it feeds. 



