1881.] OF THE INDIAN PYTHON. 961 



incubation, in the early part of July, when she left her eggs for a 

 few hours, returning to them again however and coiling herself up 

 as before, though now the regularity of her folds was not so great 

 as it had been })reyiously. On July 18th (that is, after a period of 

 forty-three days from the date of laying), as the eggs were evidently 

 decomposing, they were removed ; and their state on examination 

 was found to be very similar to that observed by Mr. Sclater 

 on the previous occasion. Several of those examined showed no 

 traces of having been impregnated ; at least, no signs of any develop- 

 ment inside remained ; one or two, however, contained embryos, one 

 of which was about 1 1 inches long, and had its scales well developed. 

 From tlie discrepancies existing between the observations of Valen- 

 ciennes and those made here previously on the temperature of the 

 incubating Pythoness, it seemed highly desirable to utilize the 

 opportunity afforded by this last instance for a further and more 

 extensive series of observations on the phenomenon in question. 

 Mr. Zarabra, of the well-known firm of Negretti and Zambra, who 

 had himself taken part in the observations made in 18G2, was kind 

 enough to give me his most valuable aid and assistance in this inves- 

 tigation. He not only sujiplied us with excellent self-registering 

 thermometers of the newest pattern and most delicate make, but was 

 also kind enough to attend regularly — often, I fear, at consider- 

 able inconvenience to himself — to superintend and take the ne- 

 cessary readings. With the assistance of Mr. Bartlett, Mr. Clarence 

 Bartlett, and the keeper of the reptiles, J. Tyrrell, Mr. Zambra and 



1 were thus enabled to take a very considerable number of observa- 

 tions on the point in question, with instruments of a more accurate 

 kind than had been available for our predecessors. Our first obser- 

 vations were taken on June 14th, about nine days after the eggs were 

 laid ; and they were continued thence without intermission, at intervals 

 of two or three days, till the eggs were removed on July 18th. The 

 readings were always taken about the same time of day, from 12 to 



2 o'clock, in order to avoid any differences that might be due to the 

 diurnal variation of tempei'ature. Following Mr. Sclater' s example, 

 we took a double series of observations, one set on the incubating 

 female, another on the male of the same species, which, after it had 

 been removed from the female when the eggs were laid, was kept in 

 the cage next to that of the female under conditions practically 

 identical. The temperature of the Snakes was ascertained, first by 

 placing the thermometer on the surface of their bodies, and then by 

 placing it between the folds of their coils. In each case their bodies 

 were covered by the blankets under which they usually rest ; and, as 

 far as possible, the different readings, of which we usually took three 

 in each set, were obtained in as many different places in the coils, 

 one towards the centre, the othersj 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. 



Proc. Zool. Soc— 1881, No. LXII. C2 



