608 CLASS XVII. 



year (summer-sleep) as BRUGUIERE asserted, was afterwards con- 

 tradicted by DESJARDINS, according to whom, on the contrary, this 

 animal, when it is summer with us, and thus during the winter 

 .season of that island, falls into its periodic sleep 1 . 



The arrangement of mammals, derived by KAY and KLEIN 

 chiefly from the digits and nails, by LINNAEUS from the teeth, was 

 improved by STORR, CUVIER and others, and advanced to greater 

 perfection especially by the physiological and embryological views 

 of OWEN. 



1 At the island Mauritius from June to November, Ann. des Sc. nat. xx. p. 180, 

 according to TALFAIB from April to November, Proceedings of the Zool. Soc. I. 1830, 

 p. 89 ; the temperature, however, does not need to fall to 20 centigr. ; they sometimes 

 sleep even at 26. Ann. des Sc. nat., Seconde Se"rie, n. p. 316. 



On hybernatiou may be compared G. MANGILI, J. A. SAISSY, PRUNELLE, J. F. 

 BERGER, PASTRE and others cited in the first edition of my handbook, to which I now 

 add: OTTO De Animalium per hyemem dormientium vasis cephalitis, Nov. Act. Acad. 

 Ccesar. Leopold. Carol. Tom. u. MARSHALL HALL on Hylernation, Phil. Trans. 1832, 

 Part 2, pp. 335 360, the same in TODD'S Cydopced. u. pp. 764776, and H. C. L. 

 BARKOW Der Winterschlaf nach seinen Erscheinungen im Thierreich, Berlin, 1846, 8vo, 

 in which last work may be found the fullest account of the entire literature on this 

 subject. 



