66 Proceedings of the Royal Society of Victoria. 



It is clear, therefore, that there are grades of temperature, and 

 that the mammals which are classed lowest on anatomical 

 grounds are not only of the lowest temperature, but also of the 

 greatest range, and they are likewise, of all mammals, those 

 which are under the strongest and most direct influence of the 

 temperature of the environment. 



Similar, though much less complete connecting links may be 

 seen in the case of birds. The lowest of birds are the Ratitae, 

 or Cursores, and these appear to have the lowest temperature. 

 Mr. Ernest Le Souef, with an amount of obliging trouble 

 which may be conceived, took for me in the Melbourne Zoological 

 Gardens observations on the temperature of the emu. These are 

 the lowest records of bird temperatures of which I know. They 

 averaged 39*5°, while all the birds above the Rati tee are invariably 

 over 40\ The temperature of thirty-six fowls, taken quietly by 

 night from their perches, averaged 41° exactly, while that of 

 twelve, lifted from the nests in which they were brooding, was 

 4T4". Numbers of fowls caught while roaming about averaged 

 41 -3 U , but these of course were always warmed up previously by 

 a little violent exercise. Turkeys stand about the same level ; 

 ducks are stated, on good authority, to be lower ; but I have 

 found for these birds, from a fairly large number of observations, 

 an average of 42T". The temperatures ot birds of the more 

 intelligent orders is generally somewhat higher. If we exclude 

 the birds of prey, we might say that in all orders above the 

 anseres, grallse and gallinse the temperature ranges over 42". It 

 would be a matter of interest to secure some observations of the 

 temperature of the apteryx, in order to determine whether the 

 lowest of birds shows by its body warmth in some degree the 

 same reptilian affinity which the monotremes exhibit. In that 

 case there would be reason to believe that the rest of the Ratitse 

 would correspond closely to the Marsupials, being a connecting 

 link, but much closer to the higher forms than to the lower. 



In a very general way, and not forgetting numerous limitations 

 and contradictions, it may be said that bodily activity depends on 

 body temperatures, that creatures such as insects, and reptiles are 

 active only when warmed up from without, but become torpid 

 with decreasing temperature. The type in which activity is 

 generally habitual, maintains its own body temperature. This is 



