22 MR. EDAVARD DEGEN ON THE 



The Postfrontals, which are joined laterally to the single parietal 

 bone by means of ordinary sutures, and which extend the whole 

 length of the parietal as far backwards as the supratemporal 

 bones, complete the cranial roof. They form a single plate in the 

 present species, with every trace of their former sutures com- 

 pletely obliterated through fusion of the two component parts 

 of which they consist in a great number of Lizards. This is a 

 condition found to exist also in Laceria simonyi, L. atlantica, 

 L. ocellata, L. viridis, L. galloti, L. dugesii, and L. Icevis (in 

 the latter sj)ecies the squamosal also fuses with the postfrontal 

 plate). In Lacerta jacksoni these bones are on the same hori- 

 zontal plane with the parietal to their outermost margins, which 

 in so many of the Lizards of the " imoralis " group are strongly 

 convex and appreciably bent downward towards the temporal 

 foramen., 



A similar feature, which imparts such a quadrangular 

 aspect to this portion of the skull, is observable in the case 

 of Lacerta simonyi* , L. atlantica^ L. ocellata, L. viridis, L. galloti, 

 L. dugesii, L. Icevis, Algiroides nigropunctatus ; and among 

 L. viuralis forms in the varieties nigriventris and serpa. 



Frontal. — Originally paired (in very young specimens) it is 

 single in the skull before me as well a,s in the majority of the 

 members of this genus when adult. Its interorbital width, at 

 the narrowest part of its anteiior portion, measvires exactly one- 

 half of its posterior and widest portion, which is to be found in a 

 line drawn between supraocularia 4, the latter coinciding approxi- 

 mately with the fronto-paT-ietal sutui-e. In proportion, therefore, 

 this interorbital width is greater than in most of the muralis-\\kQ 

 forms, except for the skull of a male specimen of the typical form 

 from Vienna, which is also greatly depressed. In the length of 

 the skull this dimension is contained six times ; whereas in the 

 majority of skulls belonging to the muralis group it varies 

 between seven and eight times. It fm^ther equals the width of 

 supraocularia 2 and 3 ; also that of the space between the innei* 

 dentary ridges (laminae horizontales) of the maxillary bones 

 (measured across the apertura narium interna), and is of the 

 same length exactly as the columella cranii (epipterygoid, Parker). 

 Equally distinguished in respect to this broad interorbital 

 diameter are — apart, again, from all the previously enumerated 

 Atlantic Island forms and others named — the skulls of L. agilis 

 and Icevis, and of the more typical viuralis forms those of 

 L. cJdorogaster, L. saxicola, and L. derjugini f. Further, in 

 Algiroides nigrop>'anctatus this region is also of a broader type ; 

 but according to Siebenrock J it differs in the persistence of the 



* Cf. " Das Skelet der Lacerta simom/i Steind. und dev Lacerfcenfamilie iiber- 

 liaupt," vcn Friedrieli Siebenrock, Sitzuiigab. Kais. Akad. der Wissenschaften iu 

 Wien, vol. ciii. part i., April 1894, Taf. ii. figs. 8 & 11. 



t Cfr. L. von Mehely, " Materialieii zu einer Sj'stematik und Phylogerie der 

 Mnralis-aluiliclien Lacevten," Ann. Mas. Nat. Hungarici, Band vii. 1909, tab. xix. 

 fio-. 9 & tab. xxii. figs. 3 & 6. 

 ■ji.c^p. 23. 



