ME. G. A. BOULENGER ON LIZA EDS 



Text-figure 2, postnasal, is exceptional ; g { 6 , Zorleni, Ron- 



mania) occurs in the vars. chersonensis and 

 exigaa, but never in the typical form ; h { 6 , 

 Lepsinskaja Staniza), in which the anterior 

 loreal is suppressed, or fused with the post- 

 nasals, is to be found in many specimens of 

 the var. exigua; ^ ( d , Suchum Kaleh) is due 

 to a fusion of the upper postnasal with the 

 anterior loreal ; k {2 , Vladikaukas) is of 

 very exceptional occurrence, but highly inter- 

 esting as reproducing the condition normal in 

 L. viridis, the frontonasal being in contact with 

 both upper postnasal and anterior loreal. 



The arrangement in h and e are both frequent 

 in L. vivipara ; one postnasal followed by one 

 anterior loreal is normal in L. mnralis and 

 several species of the same group, whilst other 

 species of the latter, as well as L. 2)arva, 

 viridis, and ocellata, have normally two super- 

 posed postnasals followed by a single anterior 

 loreal. Absence of the anterior loreal is not 

 infrequent in L. viridis and L. vivipara. 



As a further stage of evolution in the genus 

 Lacerta, I regard the participation of the rostral 

 to the border of the nostril, as in L. viridis and 

 ocellata, and more or less constantly in some 

 of the members of the L. muralis group. A 

 step further still, the nasal portion of the rostral 

 becomes detached as a small shield in front of 

 the nostril, as in some specimens of L. dan- 

 fordii, which in this respect shows the farthest 

 departure from the primitive type in the genus 

 Lacerta. In one of the specimens of L. agilis 

 (text-fig. 2, c) and in some L. vivipara, it is 

 the lower part of the nasal which has been 

 severed to form a distinct shield between the 

 rostral and the nostril. The presence of this 

 additional shield has lately been used as a 

 specific character, but it is never constant, and 

 it should be regarded as an individual anomaly. This will probably also prove to 



End of snout in Lncerla ar/Uis. to show 

 v:ii-iatioiis in the shields around the nostril. 



