HERPETOLOGY OF THE GRAND DUCHY OF BADEN. 19 



tend to reappear in the female, sometimes with the curious 

 phenomenon of a greater or less change in tint, consequent 

 doubtless on physiological causes. The mento-ccerulea variety 

 is certainly a local fashion, so to speak, and it deserves notice 

 that the distinguishing blue patch on the throat is in many 

 localities of the most ephemeral nature ; in others it is retained 

 long after the honeymoon, and in some again the lizards are 

 perpetually thus coloured.* Finally, this feature is not rarely 

 confined to the male, but elsewhere equally conspicuous in both 

 sexes (see de Bedriaga, * Beitrage zur Kenntnis der Lacerti- 

 denfamilie,' p. 67). 



Hence the unstable character of these periodical variations in 

 colour does not preclude the possibility of their becoming fixed 

 under certain conditions, and it may conversely be urged that 

 many now permanent tints may have been at a former period 

 more or less short lived. 



In this category can be placed the blue of the Faraglione 

 Lizard and other analogous varieties, to which I hope to recur 

 later, merely noting here that the throat of the male is again the 

 most brilliantly coloured portion of the body, that of the female 

 being much less vivid ; but in neither case does the blue appear- 

 ance of the lizards entirely vanish during the summer and 

 autumn, whereas the blue tinge occasionally suffused over the 

 body of the common Wall Lizard is most volatile. 



L. vivipara and agilis offer similar examples of blue colouring, 

 during the pairing season, on the throat and lower surfaces, 

 some Kussian forms of the latter having, according to Bedriaga, 

 a mark on the throat analogous to that of L. viridis mento- 

 ccerulea. 



As the intensity of brilliant colours is generally considered to 

 diminish if light be excluded, the behaviour of some specimens 

 of L. agilis, which I had occasion to forward a day's journey to 

 Prof. Leydig, may be worthy of notice to illustrate that the 

 reverse sometimes takes place. He writes : — " On opening the 

 box several of the males were of a light green, almost phosphor- 



* In parts of Southern Italy I was surprised to find that L. viridis 

 exhibited, even in the height of spring, no signs of blue colouring about the 

 head; whilst with others captured near Lake Como the blue was hardly 

 diminished in intensity even in autumn. (The Dalmatian viridis — var. 

 major, Boul. — is entirely devoid of this peculiarity.) 



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