844 



N(yrE ON THE TEMPERATURE OF ECHIDNA 

 ACULEATA. 



By H. 8. Halcro Wardlaw, D.Sc, Linnean Macleay Fellow 

 OF THE Society in Physiology. 



(From the Physiological Laboratory of the University of Sydney.) 



(Witli two Text-figures). 



In a previous communication, the present writer has recorded 

 a number of observations of the rectal temperature of Echidna 

 ac.nl eata (Wardlaw, 1915). The observations were made at 

 different times of the day, and during different seasons of the 

 year. As the temperatures showed considerable variations, even 

 outside of th6 periods during which the animals were hibernating, 

 some difficulty was experienced in arriving at an estimate of 

 their normal waking temperature. Average values calculated 

 from results varying like those obtained have no precise meaning. 

 Yet to give the range of variation alone is hardly sufficient : a 

 central value is necessary as a point of departure. 



These results, therefore, have been submitted to a further ex- 

 amination, in which the graphic method of statistical analysis, 

 due to Galton, has been applied in the manner described in a 

 former paper (Wardlaw, 1917). Tn this w^ay, it has been shown 

 that the observations of temperature are not distributed at 

 random over their whole range of variation, but occur more fre- 

 quently in the vicinity of certain values, and that the tempera- 

 ture of this animal has certain definite most probable values for 

 different times of the day at different seasons of the year. 



In the accompanying diagrams (Text-figs. 1 and 2), the fre- 

 quency of occurrence of different temperatures of Echidna, outside 

 of the periods of hibernation, have been plotted. Temperatures 

 of the animals are measured along the abscissae. The relative 



