go INTRODUCTION 



manner of their parents. The first shedding of the 

 outer coating of the epidermis follows soon after 

 birth ; not before then does the young take to food. 



No snake appears to be able to breed before it is 

 four years old. 



Well-authenticated instances of different species 

 interbreeding are unknown, but specimens inter- 

 mediate between Viper a bents and V. aspis, and 

 between V. berns and V. ammodytes, have been 

 assumed, with much probability, to be hybrids. 



