258 PHYSIOGNOMY OF PLANTS. 



its southern extremity, is entirely within the tropical zone), as Bru- 

 guiere had before observed, the hedgehog-like Tenrecs (Centenes, 

 Illiger), one species of which (C. ecaudatus) has been introduced 

 into the Isle of France, sleep during great heat. Desjardins makes, 

 it is true, the objection that the time of their slumber is the winter 

 season of the southern hemisphere ; but in a country in which the 

 mean temperature of the coldest month is 3 Reaumur (6. 75 Fahr.) 

 above that of the hottest month in Paris, this circumstance cannot 

 change the three months' " summer-sleep" of the Tenrec in Mada- 

 gascar and at Port Louis, into what we understand by a winter-sleep, 

 or state of hybernation. 



In the hot and dry season, the crocodile in the Llanos of Vene- 

 zuela, the land and water tortoises of the Orinoco, the huge boa, and 

 several smaller kinds of serpents, become torpid and motionless, and 

 lie incrusted in the indurated soil. The missionarry Grili relates 

 that the natives, in seeking for the slumbering Terekai (land tor- 

 toises), which they find lying at a depth of sixteen or seventeen 

 inches in dried mud, are sometimes bitten by serpents which become 

 suddenly aroused, and which had buried themselves at the same time 

 as the tortoise. An excellent observer, Dr. Peters, who has just 

 returned from the East Coast of Africa, writes thus to me on the 

 subject : " During my short stay at Madagascar, I could obtain no 

 certain information respecting the Tenrec ; but, on the other hand, 

 I know that in the East of Africa, where I lived for several years, 

 different kinds of tortoises (Pentonyx and Trionchydias) pass months 

 during the dry season of this tropical country enclosed in the dry, 

 hard earth, and without food. The Lepidosiren also, in places where 

 the swamps are dried up, remains coiled up and motionless, encased 

 in indurated earth, from May to December." 



Thus we find an annual enfeeblement of certain vital functions in 

 many and very different classes of animals, and, what is particularly 

 striking, without the same phenomena being presented by other 

 living creatures nearly allied to them, and belonging to the same 

 family. The northern glutton (Grulo), though allied to the badger 

 (Meles), does not, like him, sleep during the winter : whereas, accord- 

 ing to Cuvier's remark, " a Myoxus (dormouse) of Senegal (Myoxus 

 coupeii), which could never have known winter-sleep in his tropical 



