COLORATION AND ITS INTERPRETATION 81 



The same writer refers to the much brighter colouring of 

 young vipers, as compared with very old specimens. A much 

 more marked change in colour occurs, however, in the Malay 

 snake known as Wagler's viper (Lachests wagleri), which in the 

 young state is generally green while in the adult it tends to 

 blackish. The protective nature of this colouring, at least in 

 the young condition, is referred to in the sequel. This viper 

 also exhibits great variation in colour apparently independent 

 of either age or sex. Neither does it seem that these variations 

 are altogether local, seeing that both the first and the third of 

 the under-mentioned colour-types occur in Borneo, while the first 

 and fifth are recorded from Celebes. These variations, according 

 to the British Museum Catalogue of Snakes, are as follows : — 



"A. Green above, with white cross-lines edged behind with 

 blue or purple, or with two dorsal series of small spots or cross- 

 bars of the same colour ; a white line on each side of the head, 

 passing through the eye, edged below with blue or purple ; 

 belly white or pale green, with or without black edges to the 

 ventrals ; end of tail usually red or reddish brown. 



" B. Green above, with small black spots or cross-bands ; a 

 black streak on each side of the head, passing through the eye ; 

 yellow beneath, with or without black edges to the ventrals, 

 with a series of small black spots on each side ; end of tail red. 



" C. Yellowish green above, the scales edged with dark 

 bottle-green ; dark cross-bands of the latter colour ; some 

 specimens dark bottle-green above, with scattered yellowish 

 green dots; ventrals yellow, edged with dark green, with a 

 series of round green spots on each side, or dark green with 

 yellow spots ; end of tail dark green or blackish. 



" D. Green above, with the scales black-edged, with bright 

 yellow black-edged cross-bands, or black with yellow cross- 

 bands ; head black, spotted with yellow ; belly bright yellow 

 or yellow and green ; ventrals black-edged ; end of tail black. 



" E. Green above, with large brick-red, black-edged spots ; 

 white beneath, with black spots and marblings powdered with 

 brick-red ; end of tail red." 



Such differences, whether they be individual, or character- 

 istic of local races, demonstrate how easily new specific types 

 can be evolved from existing forms. 



In the New York Zoological Park some remarkable colour- 



6 



