BY H. S. HALCRO WARDLAW. 233 



and Martin concluded that Echidna is the lowest on the scale 

 of warm-blooded animals. 



But there is a class of mammals whose temperatures are at 

 times subject to very great variations- the class of hibernants. 

 The members of this class are not confined to any one group of 

 animals, and among them is to be numbered Echidna (N. de 

 Miklouho-Maclay, Martin, Inc. cit.). During the winter-months, 

 animals of this class allow their temperatures to sink towards 

 that of the external air, and behave like cold-blooded animals 

 for periods of varying duration. 



As to the temperatures of these animals outside of the periods 

 of hibernation, the data available are rather few in number, and 

 different observers are not unanimous in their opinions. Pembrey 

 {loc. cit.) states that, with regard to temperature, the behaviour 

 of hibernants in their waking-state is practically the same as that 

 of other warm-blooded animals. Merzbacher(8), on the other 

 hand, is of the opinion that the temperature of hibernants in 

 their waking-state is rather lower than that of other mammals, 

 and is subject to much greater variations. He cites his own 

 observations and those of Saissy(12), who gives the waking-tem- 

 perature of the bat as STC; BertholdO), who states that the 

 normal waking-temperature of the dormouse is 29'7°C.; Barkow(2), 

 who observed temperatures ranging from 25° to 35"'C. in 

 the case of a waking hedgehog ; and of several other investi- 

 gators in support of this view. A quotation from Barkow 

 may be given as summarising their position : " Obgleich 

 die Tiere ausserhalb des Winterschlafes zu den Warmbliitigen 

 gehoren, so zeigt die Lebenswarme doch bei verminderter 

 allgemeiner Tatigkeit, wie wahrend des gewohnlichen Schlafes, 

 bei Abmagerung, oder sonstiger Krankheit, grosse JVeigung zum 

 Sinkeny Athanasiu(l), however, while admitting that the 

 waking-temperatures of hibernants are perhaps slightly lower 

 than those of other mammals, throws doubts on the reliability of 

 the low figures given by some of the above observers, and points 

 out how extremely limited is our knowledge of the temperatures 

 of hibernants in their active state, and how necessary are new 

 investigations to give us satisfactory information on this question. 



