346 THE ZOOLOGIST. 



On the 13th of July a common Ringed Snake (Tropidonotus 

 natrix) in my small reptilium laid fourteen disconnected eggs. A 

 few others were deposited both before and after the batch at 

 intervals of several days, but these were all apparently either 

 immature or addled ; the fourteen being plump, perfect eggs, with 

 the membranous envelope distinct and well formed. I inferred 

 from the snake's uneasiness and restless wanderings about the 

 cage on tbe night of the 12th that deposition was about to take 

 place, and that she was seeking an eligible spot for the purpose ; 

 accordingly, I introduced a small open box filled with moss into 

 the case, and on taking a last look before retiring about 2 a.m. I 

 observed her lying quietly therein. Six hours later, however, I 

 found her coiled on a pyramid of eggs in a distant corner of the 

 cage, encircling and surmounting them in such a way as almost to 

 conceal them — snake and eggs forming a sort of cone. She had 

 deserted the moss, and had so cleared away the gravel where she 

 was lying that the eggs rested on the wooden floor : this had 

 probably occurred as soon as the morning sun struck that part of 

 the cage. 



Looking upon this position as indubitable evidence of an 

 intention to incubate, I commenced to take observations of the 

 temperature at once, and continued to record them regularly 

 every four hours until her desertion of the eggs six days after- 

 wards, making also frequent trials between these periods so that 

 no unexpected exacerbation or development of other phenomena 

 might escape notice. I employed for the purpose three carefully 

 tested clinical thermometers, and as far as possible made use of 

 all the surroundings as standards of comparison — the woodwork, 

 gravel, the air inside and without the cage, and the other snakes 

 — in order that the degree of retention and subsequent evolutions 

 of heat derived from the direct sunshine in every case might be 

 allowed for in calculating external influences. The temperatures 

 which I have preserved as reliable were all taken between the 

 coils or in the centre of the mass, those obtained by the mouth 

 and anus being attended with so much disturbance that I hesitate 

 to consider them trustworthy. The results of these experiments 

 may be epitomised as follows: — There was a minimum elevation 

 of 1*8° (Fahrenheit) above the surrounding atmosphere and 

 objects, to be observed as constantly at the warmest hour of the 

 day, when the sun was pouring full upon her, as in the middle of 



