SEX AND REPRODUCTION 73 



of incubation of the Malay python is thus two and a half 

 months. 



Another instance of a python (this time an African species) 

 incubating in captivity occurred in the Jardin des Plantes, 

 Paris, in the year 1841. A fourth case took place in the 

 menagerie at the Tower of London in the year 1828. In this 

 instance the snake had been more than two years in the col- 

 lection when she produced fourteen or fifteen eggs, none of 

 which, however, were hatched, although the mother evinced 

 great anxiety for their preservation, coiling herself round them 

 in the form of a cone, of which her head formed the summit, 

 and guarding them from injury with solicitude. The eggs 

 appear to have been shown to visitors by the keeper, for it is 

 stated that they were only visible when she was occasionally 

 roused, and raised her head, which formed the cover of the 

 pile. Every time, however, she resumed her normal position 

 as quickly as possible, allowing the spectator only a momen- 

 tary glance at her treasures. 



If there be any truth in the story of its swallowing its young, 

 the most remarkable instance of maternal care among reptiles 

 occurs in the viper. On the face of it, this occurrence seems 

 sufficiently improbable, and its possibility has been denied, 

 Nevertheless, popular beliefs are often founded on fact. The 

 question has been considered by Dr. G. Leighton ; and although 

 he has been unable to cite any definite instance of the occur- 

 rence of the phenomenon, he shows that some of the objections 

 which have been urged against it are based on a misinterpreta- 

 tion of anatomical facts, and demonstrates that there is nothing 

 impossible in its taking place. As the gullet of an adder is 

 perfectly capable of containing the body of a field-mouse, and 

 as frogs are known to live for a considerable time after being 

 swallowed by snakes, there is no reason why young adders 

 should not be swallowed by their parent without being killed. 

 The question remains, however, to be proved by positive evi- 

 dence. "Of the possibility of the phenomenon," writes the 

 author, " we have not the slightest doubt, of the probability of it 

 we have considerable doubt ". 



In the case of the python at Colombo about one hundred eggs 

 were laid. In this great fertility pythons apparently are ahead 

 of viviparous snakes, although exact information regarding the 



