CHAPTER XII 



COLOUR VARIATION IN LIZARDS 



THE PKOBLEM FACTOES CONCERNED EVIDENCE OF SEX 



INFLUENCE EVIDENCE OF AGE INFLUENCE — CON- 

 CLUSION REFERENCES. 



From what has been said in the foregoing pages under 

 the headings of the various species of British lizards, 

 it will be quite evident to the reader that there is 

 a very marked degree of colour variation to be foimd 

 in these reptiles. In that respect they resemble the 

 snakes, in which the same phenomenon is equally pro- 

 nounced. The present writer has on various previous 

 occasions dealt with the problem as presented in the 

 order of serpents, and a reference to the literature in 

 that group is appended at the end of this chapter. It 

 remains, therefore, to review the principles appHcable 

 to the subject with special reference to the lizards, 

 and to endeavour to ascertain to what extent the 

 processes of colour variation in lizards are due to the 

 same or similar causes as those proved to be responsible 

 for the colour variation of serpents. 



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