36 Lacerti(he. 



AccordiiiL? to the theory here propounded, one may distinguish three 

 grades in the dorsal pattern of striated members of the genus Lacerta, 

 l>eginning with the most primitive : (a) a light A^ertebral stripe, (h) 

 a dark vertebral stripe, (r) no vertebral stripe or series of spots. 

 Each of these leads independently to the ocellated, spotted, reticulated, 

 cross-barred, or uniformly coloured types. 



In the evolution of colours, leaving out of consideration the bright 

 yellow, red, or blue tails which form part of the juvenile livery of 

 some Lizards,* the vivid hues (yellow, green, blue, or red) appear 

 first as a seasonal character of the breeding male, before persisting 

 throughout life ; they are afterwards passed on to the female. In all 

 Lacerta the young at birth are black and white, grey, or greyish-brown 

 (blackish in L. vivipara). In L. agilis the typical form retains the 

 grey or brown colour, the males being green on the sides during the 

 spring and early summer only ; but very exceptionally the green may 

 extend to the upper surface in males, and naay appear on the sides in 

 females ; in the vars. chersonensis and exigua, some specimens of wdiich 

 are further advanced in the direction of L. viridis, males ai'e very 

 often, and females less frequently, green all over, and this colour 

 is retained beyond the breeding season. In L. viridis both sexes are 

 usually green when adult, and at all seasons ; but in some localities 

 the females retain throughout life the brown colour of the young. 

 Blue over the throat and the sides of the head, or as spots or ocelli on 

 the flanks, occurs more frequently in males than in females, and in 

 some forms is the exclusive endowment of the former. Green may be 

 replaced by bright yellow (upper parts of L. ocellata, L. mnralis, var. 

 nigriventris, lower parts of L. viridis). Red, as an intensification of 

 yellow, passing through orange, adorns the lower parts of many 

 Lizards, especially during the breeding season, or, derived from 

 reddish brown, the back of certain specimens of L. agilis (var. rubra) ,^ 

 appearing in the same order as does the green ; or it may accompany 

 the blue as part of the nuptial garb in the males {L. peloponnesiaca). 



The genus Lacerta may be divided into six sections : 



of that genus as varieties of L. muralis (I.e., pp. 401, 404). As I have abeady 

 pointed out, the lack of judgment in the appreciation of structural characters 

 detracts much from the value of his otherwise admirable memoir. 



* Lacertida;, Teiidte, Scincidte, Agamida?. As regards the coloration of the 

 rest of the body, I cannot recall a single instance in Lizards in which the 

 young is more brightly coloured than the adult, although in many cases the 

 markings are more sharply defined or the patterns more elegant. This is 

 remarkable, considering that the reverse is the case in many Snakes, Tortoises, 

 and Batrachians. 



