io6 HIBERNATING ANIMALS. [chap. v. 



reptiles possess great powers of cutaneous absorption. At 

 Maldonado, 1 found one in a situation nearly as dry as at 

 Bahia Blanca, and thinking to give it a great treat, carried 

 it to a pool of water ; not only was the little animal unable 

 to swim, but I think without help it would soon have been 

 drowned. 



Of lizards there were many kinds, but only one {Procto- 

 tretus multimaculatus) remarkable from its habits. It lives 

 on the bare sand near the sea coast, and from its mottled 

 colour, the brownish scales being speclded with white, 

 yellowish-red, and dirty blue, can hardly be distinguished 

 from the surrounding surface. When frightened, it attempts 

 to avoid discovery by feigning death, with outstretched legs, 

 depressed body, and closed eyes : if further molested, it buries 

 itself with great quickness in the loose sand. The lizard, 

 from its flattened body and short legs, cannot run quickly. 



I will here add a few remarks on the hibernation of 

 animals in this part of South America. When we first 

 arrived at Bahia Blanca, September 7th, 1832, we thought 

 nature had granted scarcely a living creature to this sandy 

 and dry country. By digging, however, in the ground, 

 several insects, large spiders, and lizards were found in a 

 half torpid state. On the 15th, a few animals began to 

 appear, and by the i8th (three days from the equinox), every- 

 thing announced the commencement of spring. The plains 

 were ornamented by the flowers of a pink wood-sorrel, wild 

 peas, Oenotheras, and geraniums ; and the birds began to 

 lay their eggs. Numerous lamellicorn and heteromerous 

 insects, the latter remarkable for their deeply sculptured 

 bodies, were slowly crawling about ; while the lizard tribe, 

 the constant inhabitants of a sandy soil, darted about in 

 every direction. During the first eleven days, whilst nature 

 was dormant, the mean temperature, taken from observa- 

 tions made every two hours on board the Beagle ^ was 51° ; 

 and in the middle of the day the thermometer seldom 

 ranged above 55°. On the eleven succeeding days, in 

 which all living things became so animated, the mean was 

 58°, and the range in the middle of the day between sixty 

 and seventy. Here then an increase of seven degrees in 

 mean temperature, but a greater one of extreme heat, was 

 sufficient to awake the functions of life. At Monte Video, 

 from which we had just before sailed, in the twenty-three 

 days included between the 26th of July and the 19th of 

 August, the mean temperature from 276 observations was 



