232 TEMPERATURE OF ECHIDNA ACHLEATA, 



temperatures of two specimens to be 28-3° and 26'95°C. R. von 

 Lendenfeld(6) gives the ordinary blood-temperature of the animal 

 as 28°C., although he says it may rise as high as o^C. Semon(13) 

 found that the cloacal temperatures of the seven Echidnas, which 

 he was able to observe, ranged from 26-5° to 34-0°C., whilst 

 Sutherland(15), observing fourteen animals, found temperatures 

 ranging from 22° to 36'C. The two latter observers recorded 

 the temperatures of the air as well as those of the animals. The 

 only conclusions to be drawn from the above small number of 

 observations seem to be those expressed by Semon, that Echidna 

 is not strictly to be classed either with poikilothermal or with 

 homoiothermal animals; it has a body-temperature which stands 

 in no direct relation to the temperature of the external air, but 

 which undergoes uncommonly large variations. 



Later, C. J. Martin(7) studied the behaviour of the temperature 

 of Echidna, when the external temperature was rapidly varied 

 in a detinite and regular manner. Under these circumstances, 

 it was shown that the temperature of Echidna undoubtedly 

 depended on that of the surroundings. In experiments on three 

 animals, for example, when the temperature of the surroundings 

 rose from 5° to 35° in 6-7 hours, the temperature of the Echidnas 

 rose from 25-5° to 34-8°, or Q-S'C., from 27'6° to 40-0°, or 12-4°C., 

 and from 29-1° to 37-1°, or 8"0°C., respectively. It must be 

 noted, however, that under circumstances such as these even the 

 temperatures of higher mammals showed a degree of dependence 

 on the external temperature much greater than usual. In the 

 case of a rabbit, when the air-temperature fell from 40° to 5°, or 

 35°C., in about five hours, the temperature of the animal fell 

 from 41-6° to 37-5°, or 4'1°C., in the same time. In the case of a 

 cat, when the same fall in the external temperature occurred in 

 an equal time, the temperature of the animal fell from 39-9*' to 

 38-5°, or 1-4°C. The variations of the temperatures of reptiles 

 (blue-tongued lizards) in similar experiments followed exactly 

 those of the temperature of the surrounding air. 



Under the conditions of these experiments, therefore. Echidna 

 behaved in a manner intermediate, with regard to the regulation 

 of its temperature, between that of reptiles and that of mammals; 



