436 SNAKES. 



even in a viper the young have been produced in a 

 t ... 



membrane. This was the case with Vipera nasicornis at 



the London Zoological Gardens, on Sunday, November 



6th, 1 88 1, that gave birth to forty-six viperlings. Some of 



them had no vestige of membrane clinging about them ; 



others had, but burst it immediately and began to crawl ; 



while yet others did not burst their ' shell ' at all, — if indeed 



so filmy and thin a membrane could be called a shell, — 



but died within it. When the membrane burst, it was 



seen to collapse and shrivel up into nothing, as children's 



air balls do when they are torn ; but the texture of these 



balls is strong in comparison with the extreme tenuity of the 



viperine ^^^ tunic. Yet it was strong enough to contain 



a young one, as in the case of those unbroken. There 



is no means of ascertaining the precise length of time 



this viper had been in captivity ; but as her young ones 



had all such fully-developed fangs, and the precocity to 



strike and kill a mouse as soon as born, this was probably 



another case of postponed deposition. On a previous 



occasion, September 1875, a family of young vipers born at 



the Ophidarium were ' some quite clean and otJiers with the 



remains of the egg covering about them! The quotation from 



my notebook refers to the Daboia of India, ' Russell's viper ' 



( Vipera elegans). Still these may be exceptional and possibly 



abnormal cases, but are examples worth noting, and another 



proof of the many exceptions to what we are accustomed 



to believe invariable rules. 



White, in his History of Selborne, mentions the capture 



of a viper in which he found fifteen young, the shortest 



being seven inches. They were active, spiteful, and 



