Lacerta. Ill 



a light vertebral streak, which has been retained in L. cfesaris. 

 L. atlantiea, although occupying a somewhat isolated position, has 

 too much in common, as regards both structure and coloration, with 

 L. galloti to be considered as not related to it, combining features 

 more primitive (lower number of ventral plates and serrated collar), 

 and more advanced (denticulation in front of the ear). It must be 

 borne in mind that the difference in the dorsal scales between 

 L. atlantiea and L. galloti is about the same as that which separates 

 L. jjrinceps from L. ocellata, both of which I regard as directlj"^ 

 derived from L. viriclis. 



It is clear therefore, that the relationships of the species of this 

 group cannot be expressed by a linear arrangement. Their aflBnities 

 seem to be as follows : 



L. galloti. 

 L. cdlantica. I L. stehlini. L. simonyi. 



I L. caesaris. | | 



I I ZZJ 



L. viridis-ocellata. 



The view which I first expressed in 1891* as to the relationship of 

 L. galloti and L. simonyi to L. ocellata has been supported by P. Lehrs 

 in 1909. t A further argument in favour of the derivation of this 

 group from L. ocellata is found in the presence of a single postfrontal 

 bone, as in that species, instead of two as in L. agilis and L. viridis-l 

 Whilst the two bones are distinct in young L. ocellata, Siebenrock has 

 ascertained that they are fused from the earliest youth in the species 

 which constitute the Section Gallotia.% The character must be used 

 with discretion for systematic purposes, as fusion of the two elements 

 may take place in the adult of some of the species, L. viridis\\ and 

 L. muralis for instance, but it is of importance, as in this case, in the 

 attempt at tracing the derivation of forms. 



6. LACEETA ATLANTICA. 



Zootoca galloti, part., Gray, Cat. Liz. p. 30 (1845). 



Lacerta atlantiea, Peters & Doria, Ann. Mus. G-enova, xviii, 1882, 



* Proo. Zool. Soc. 1891, p. 201. 



t Zool. Jahrb., Syst. xxviii, p. 93. 



t Cf. Siebenrock, Sitzb. Ak. Wien, ciii, 1, 1894, p. 240. 



§ Unless the skull be disarticulated, it is necessary to examine the inner 

 side of the parietal region to make certain as to this character, which is 

 obscured on the upper surface by the dermal incrustations. 



II The postfrontal is single in the only skull of the var. schreiberi (adult 

 male) examined. 



