64 RIALDONADO. 



frequently made their peculiar noise, which is a 

 low abrujDt gi'unt, not having much actual sound, 

 but rather arising from the sudden expulsion of 

 air : the only noise I know at all like it, is the first 

 hoarse bark of a large dog. Having watched the 

 four from almost within arm's length (and they 

 me) for several minutes, tliey rushed into the 

 water at full gallop with the gi-eatest impetuosity, 

 and emitted at the same time their bark. After 

 diving a short distance they came again to the 

 surface, but only just showed the upper part of 

 their heads. When the female is swimming in the 

 water, and has young ones, they are said to sit on 

 her back. These animals are easily killed in 

 numbers ; but their skins are of trifling value, and 

 the meat is very indifferent. On the islands in the 

 Rio Parana they are exceedingly abundant, and 

 afford the ordinary prey to the Jaguar. 



The Tucutuco (Ctenomys Brasiliensis) is a cu- 

 rious small animal, which may be briefly described 

 as a Gnawer, with the habits of a mole. It is 

 extremely numerous in some parts of the countiy, 

 but is difhcult to be procured, and never, I believe, 

 comes out of the ground. It throws up at the 

 mouth of its burrows hillocks of earth like those 

 of the mole, but smaller. Considerable tracts of 

 country are so completely undermined by these 

 animals, that horses, in passing over, sink above 

 their fetlocks. The tucutucos appear, to a certain 

 degree, to be gi'egarious : the man who procured 

 the specimens for me had caught six together, and 

 he said this was a common occuiTence. They are 

 nocturnal in their habits ; and their principal food 

 is the roots of plants, which are the object of their 

 extensive and superficial burrows. This animal 

 is universally known by a very peculiar noise 

 which it makes when beneath the ground. A 



