286 ON THE INCUBATION OF THE INDIAN PYTHON. 



remained for six weeks, without once eating, and with only one break in 

 P. Z. S. 1881, her incubation, in the early part of July, when she left her eggs for a 

 p. 961. f ew h oarS) 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 previously. 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 development inside remained ; one or two, how- 

 ever, contained embryos, one of which was about 11 inches long, and had 

 its scales well developed. 



From the discrepancies existing between the observations of Valenciennes 

 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 obser- 

 vations on the phenomenon in question. Mr. Zambra, of the well-known 

 firm of Negretti and Zambra, who had himself taken part in the obser- 

 vations made in 1862, was kind enough to give me his most valuable aid 

 and assistance in this investigation. He not only supplied 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 considerable inconvenience to himself to superintend and take 

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

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

 were thus enabled to take a very considerable number of observations on 

 the point in question, with instruments of a more accurate kind than had 

 been available for our predecessors. Our first observations 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 temperature. 

 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 



