OCR Text |
Show 962 ON THE INCUBATION OF THE INDIAN PYTHON. [Nov. 29; The observations are given in extenso, as we took them, in Table I. (p. 964). In Table II. (p. 967) I have given the average temperatures 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. 963) 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. These figures give a difference of 1°*4 F. and a little over 3o,0 F., the difference being in each case in favour of the female. The maxima 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 maximum 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°*0 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 110,6 F. in the case of the male, 160,7 F. in the female. Valenciennes found on one occasion the difference, as measured between the coils, as much as 21°*5 C. (between 18°-0 C. and 39°-5 C.) or 38°*7 F., a difference enormously greater than any we observed. It would seem therefore that, if his observations are to be relied on, throughout the case recorded by Valenciennes the female developed a far greater amount of heat than ours did, though she was kept in a cage that was apparently considerably colder •*•. As in this 1 The extreme temperatures of the air recorded by Valenciennes-who took his observations when the cages were coldest, i. c. before the fresh hot water was put in-are 17° C. and 23° 0. (62°*6 F. and 73°"4 F.) respectively. The temperature of tbe two cages in which our animals were kept was only on three occasions less than the highest in Valenciennes' series. |