38 INTRODUCTION 



exception, even in the genus to which the Adder 

 belongs. A nuptial dress is unknown in snakes. 



A special livery for the young is rather exceptional, 

 but very often the new-born is more vividly coloured 

 than its parents, and in many black varieties the 

 young is similar to the typical form. Some green 

 Tree-Boids (Chondropython and Cor alius caninus) are 

 not green, but yellowish, cream-colour, or pinkish, 

 when young, the green appearing around the white 

 spots, which are the remains of the ground colour, and 

 gradually spreading over the whole body. Conversely, 

 the young of a variety of the Pit-viper Lachesis 

 wagleri, common in the Malay Peninsula, is green, 

 and the adult black and yellow. In the young of 

 Gvayia ornata, a West African Water-snake, the 

 markings of the young are to those of the adult 

 like positive and negative in photography, the white 

 bars, forked on the sides, which extend across the 

 black back of the former being gradually trans- 

 formed into black bars on a light ground in the 

 latter ; in such a case it is impossible to decide 

 whether the dark or the light parts are to be con- 

 sidered as the ground colour. 



That the skin of many snakes contains soluble 

 colouring matter of a special kind is well known, 

 green snakes, such as Dryophis prasinus and Lachesis 

 gramineus staining the spirit in which they are pre- 

 served. Chemists have not yet paid attention to 

 this question, which requires investigation. 



