THE VOYAGE OF THE BEAGLE 81 



The next day the country continued similar to that above 

 described. It is inhabited by few birds or animals of any 

 kind. Occasionally a deer, or a Guanaco (wild Llama) may 

 be seen; but the Agouti (Cavia Patagonica) is the common- 

 est quadruped. This animal here represents our hares. It 

 differs, however, from that genus in many essential respects ; 

 for instance, it has only three toes behind. It is also nearly 

 twice the size, weighing from twenty to twenty-five pounds. 

 The Agouti is a true friend of the desert; it is a common 

 feature of the landscape to see two or three hopping quickly 

 one after the other in a straight line across these wild plains. 

 They are found as far north as the Sierra Tapalguen (lat. 

 37 30'), where the plain rather suddenly becomes greener 

 and more humid; and their southern limit is between Port 

 Desire and St. Julian, where there is no change in the nature 

 of the country. It is a singular fact, that although the 

 Agouti is not now found as far south as Port St. Julian, yet 

 that Captain Wood, in his voyage in 1670, talks of them as 

 being numerous there. What cause can have altered, in a 

 wide, uninhabited, and rarely-visited country, the range of 

 an animal like this? It appears also, from the number shot 

 by Captain Wood in one day at Port Desire, that they must 

 have been considerably more abundant there formerly than 

 at present. Where the Bizcacha lives and makes its burrows, 

 the Agouti uses them; but where, as at Bahia Blanca, the 

 Bizcacha is not found, the Agouti burrows for itself. The 

 same thing occurs with the little owl of the Pampas (Athene 

 cunicularia), which has so often been described as standing 

 like a sentinel at the mouth of the burrows; for in Banda 

 Oriental, owing to the absence of the Bizcacha, it is obliged 

 to hollow out its own habitation. 



The next morning, as we approached the Rio Colorado, 

 the appearance of the country changed; we soon came on a 

 plain covered with turf, which, from its flowers, tall clover, 

 and little owls, resembled the Pampas. We passed also a 

 muddy swamp of considerable extent, which in summer dries, 

 and becomes incrusttd with various salts ; and hence is called 

 a salitral. It was covered by low succulent plants, of the 

 same kind with those growing on the sea-shore. The Colo- 

 rado, at the pass where we crossed it, is only about sixty 



