Hibernation of Animals. 53 



is confined to the La Plata country, while his species 

 takes its place in Patagonia. 



Among the strange animals observed here were 

 the armadillos, four species being found ; some were 

 day travellers, while others only appeared at night, 

 wandering over the plains. When approached the 

 little creatures would roll up into a ball-like shape, 

 and were then safe from all but human attack. In 

 riding over the country they were frequently seen, 

 but so rapidly did they dig and burrow that it was 

 necessary to leap from the horse immediately, as 

 their hind quarters would almost disappear before 

 one could alight. 



In the woods Darwin discovered a singular snake, 

 Cophias, which, while without rattles, produced a 

 warning almost similar to the rattlesnake. The tip 

 of the tail was slightly enlarged, and as the snake 

 moved through the brush it vibrated, and, striking 

 against the reeds and grasses, produced a rattling 

 noise distinctly audible six or seven feet distant. 

 Here was also found a toad, with black upon the 

 upper surface and the brightest vermilion below, 

 living not in damp spots, but crawling about in the 

 sunlight. A remarkable mimic among the lizards 

 {Proctotretus) was noticed on the sea-shore, living 

 on the open rocks, where its close resemblance to its 

 surroundings protected it from various enemies, 

 when attacked or alarmed. Darwin was astonished 

 to see it stretch out its legs, stiffen its limbs, and 

 feign death, even closing its eyes. 



The interesting phase of life, hibernation, did not 

 escape the observant eye of the young naturalist, 



