ON THE INCUBATION OF THE INDIAN PYTHON. 287 



the centre, the others more towards the outside. The temperature of the 

 air was taken by suspending a thermometer a little way above the floor 

 of the cages ; that of the gravel in the cages by burying the bulb of the 

 thermometer in the gravel, in the same position in each cage, and over 

 the hot-water pipes which run beneath the floors of the cages. 



The observations are given in extenso, as we took them, in Table I. !* Z. S. 1881, 

 (p. 290). In Table II. (p. 292) I have given the average temperatures p- 962 ' 

 of the two Snakes, as deduced from these observations, as well as the 

 difference for each set of readings in the temperature in the two sexes. In 

 the diagrams (figs. 1 and 2, p. 288) I have recorded these averages in a 

 graphic form, the upper line marking the average temperature between the 

 folds and the middle line the average on the folds, whilst the lowest one 

 indicates the temperature of the air in the respective cages. This last curve 

 is nearly identical in the two cases, that in the male's cage averaging, 

 however, a trifle higher. Although this is the case, it will nevertheless be 

 observed that both the temperature-curves of the female are higher than 

 the corresponding ones for the male, especially the upper one. All four 

 are clearly influenced by the variations in the external medium, the 

 maxima temperatures of the snakes' bodies being attained when the air 

 is hottest or nearly so. 



Not only are the temperature-curves of the female higher, but, as 

 shown by their less amount of angularity, the temperature of the female 

 continues more constant throughout the time observed. This, no doubt, 

 may in part be due to the fact of the female being in a condition of repose 

 throughout, with no variations produced by exercise, the assimilation of 

 food, or other causes. 



Taking the averages of the first four columns of Table II., we get 

 respectively 82-98 F. and 86-03 F. as the temperature of the male, and 

 84-38 F. and 89-07 F. as that of the female, according to whether the 

 temperature is taken on the surface or between the folds. The figures 

 give a difference of l-4 F. and a little over 3-0 F., the difference being in 

 each case in favour of the female. 



The tnaxima readings obtained were, as may be seen from Table I., 

 89-6 F. (July 4) and 89-8 (July 15) for the male (surface and folds), 

 and 89-8 F. (July 15) and 92-8 F. (July 1) for the female. The maxi- 

 mum observed by Valenciennes was 41'5 C. (106'7 F.), or nearly 14 

 higher than the highest I observed. 



The greatest difference between the temperature of the air and that 

 of the surface of the two Snakes was 8-3 F. (on June 16th) in the case 

 of the male, and 9-6 F. (on June 18th) in the case of the female. The 

 greatest differences between the air and the coils were also observed on 

 the same days, and amounted to ll-6 F. in the case of the male, 16'7 

 F. in the female. Valenciennes found on one occasion the difference, as 



