Lacerta. Ill 



a light vertebral sti'eak, which has beeu retained iu L. c;tsar(><. 

 L. atlantica, although occupyiug a somewhat isolated position, has 

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

 L. (jallofi 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. atlantica and L. galloti is about the same as that which separates 

 L. princeps from L. ocellata, both of which I regard as directlv 

 derived from L. viridis. 



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

 group cannot be expressed by a linear arrangement. Their affinities 

 seem to be as follows : 



L. galloti. 

 L. atlantica. \ L. stehlini. L. simonyi. 



I L. caesaris. | | 



I I ■ i 



_ „^._ 



L. viridis-ocellata. 



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

 L. (jalJoti and L. simonyi to L. ocellata has been supported bv 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. X 

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

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

 Avhich 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. LACEKTA ATLANTICA. 



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



Lacerta atlantica, Peters & Doria, Ann. Mus. Geuova, xviii, 188-2, 



• Proc. Zool. Soc. 1891, i). 201. 



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



X Cf. Siebenrock, Sitzb. Ak. Wien, ciii, 1, 1894, p. 2-10. 



§ 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. 



i| The postfrontal is single in the only skull of the vai\ sclirelhcr'i (adult 

 male) examined. 



