ALLIED TO LACERTA MURALIS. 7 



the " deux naso-frcnalcs " of L. agilis. " Uu des caractcres distinctifs dii Lezard des 

 souches, c'est d'avoir deux plaques naso-frcnalcs, dont une, la supcrieure, est supportce 



nioitic par I'inferieure, moitie par la post-naso-frenalc (^anterior loreal) I/a 



narine n'cst jamais bordcc en arriore que par la naso-frenale inferieure, qui, chez 

 quelques individus, se trouve divisee dans le sens longitudinal de la tete en deux 

 parties moins souvcnt egales qu'inegales et, dans se dernier cas, c'est presque toujours 

 la petite partie qui est la supcrieure. D'autrcs fois, mais c'est beaucoup plus rare, 

 la naso-frenale supcrieure est iutimement soudce a la post-naso-frenale, se qui rend 

 I'entourage squameux de la narine semblable a celui du Lezard vivipare." Nothing 

 could be more contradictory. If tlie so-called upper postnasal does not touch the 

 nostril, it is not a postnasal, it is a part of the anterior loreal, as the authors them- 

 selves imply by their comparison with L. vivipam, and when the so-called lower post- 

 nasal is divided there is no difference from the condition ascribed to L. viridis. But 

 if the authors of the 'Erpetologie ' had carefully examined a larger material, they would 

 probably have found specimens which would have justified, to a certain extent, their 

 interpretation of the shields behind the nostril. I have come across a few cases, both 

 in tlie typical form and in the var. exigua, which answer to the definition in the 

 synopsis quoted above, and I cannot help thinking that such cases, which are to be 

 explained as due to a fusion of the upper postnasal with the anterior loreal, have 

 been at some time examined by them aud afterwards forgotten, thus accounting for the 

 confusion in their statements *. Irt the following series of figures (text-fig. 2), I have 

 represented the principal variations in the nasal and anterior loreal shields of L. agilis. 

 The condition in a, which I regard as the most primitive, and which agrees witii 

 that in the genus Nucras, is a very rare exception, met with by Mehely in a specimen 

 from Hungary and by me in two females, from Swanage and Lausanne ; h { 6 , Bourne- 

 mouth) and 6- ( S , Odensjo, Sweden) represent the usual state of things in the typical 

 form, and c is frequent in the var. exiijua, with this restriction, that the separation of 

 the lower part ot the nasal as a distinct shield is a rare anomaly ; d is taken from a 

 specimen from near Paris ( ? , Senart) ; e ( d , Southport) occurs sometimes in the 

 typical form, and is the rule in the var. spinalis ; / ( ? , Ringwood), in which the 

 anterior loreal is reduced to the upper half, the lower having fused with the lower 



* Many of the minor defects of the 'Erpetologie Geiicrale,' which in the last century has been the 

 recognised standard work for the study of lleptiles, are to be accounted for by the fact that the publication 

 of the ten volumes of this monumental work extended over twenty years (1834-18.54), some of them having 

 appeared long after they were written, and the process of revision and interi)()lation must have been a matter 

 of considerable difHculty, especially for the later volumes, after Dumoril had been deprived of the assistance 

 of his collaborator Bibron, whoso premature death occurred in 1848. The synopsis of the species of the 

 genus Laccrta in the appendix to the ninth volume has been prepared with extraordinary levity ; the 

 diagnosis there given of L. sHrpium (= a,jllis) may be quoted as an example :— " Ecailles du dos hexagones 

 en toit, non imbriquees, d"un brun rougeatre tachetu ou ocelle de noiratre ; dancs vcrdatres." 



