CRAXIAL CnAUACTERS OF LACERTA JACKSONI. 21 



Craxium [Fronto-pa7'ietal portion). — Squai-ish. The whole of 

 the upper surface from the anterior borders of the nasals to the 

 posterior margin of the pai-ietal quite flat, and forming an almost 

 perfectly level pla,ne. 



Denned incrustation. Evenly spread, profuse, but highly 

 porous, and covering the whole of the upper surface, including a 

 small portion of the nasal process of the prtemaxillary l)one. 



Lamina supraciliaris (text-fig. 6, A, p. 23) (Supra -orbital 

 region). Completely ossified ; 4 supraoculars, and 1 supraciliary 

 on each side. 



Supraorbital hones (text-fig. 6, B). Small ; irregularly tria.n- 

 gular and thickish, convex laterally. The internal angles termi- 

 nating in a hook-like spine and the posterior margins irregularly 

 serrated. Their lateral edges barely showing on the exterior and 

 almost wholly concealed under the first supraciliary scutes. 



Pteri/yoicl bones. Toothless ; moderately diverging immediately 

 in front of the dilated lateral processes of the basisphenoid. 



Postfrontals forming a, single plate. 



A Retrociliary present (text-fig. 6, A). 



Dermal ossification of Temporal region. Supratemporalia 1 and 

 2 partially ossified. 



Dentition. Number of teeth in preemaxillary 9 ; in each 

 maxillaiy 18. 



Nasal apertures (text-fig. 6, D). Subcircular, the longitudinal 

 diameter the greater. 



Parietal Region. — This, as in all Lacertidse, is clearly defined 

 in contour, and forms the greatest expanse of the cranial roof. 



Its anterior borders practically are coincident with the fronto- 

 parietal suture and the postorbital margins of the adjacent post- 

 frontals. Posteriorly, the parietal is produced well ba,ckwards, 

 and ends in a straight edge, the latter being the result of an 

 increased deposit of the crusta calcarea — a feature mostly absent 

 in the very young, in which this portion is concavely crescentic. 

 This edge connects the two outward and backwardly directed 

 processus parietales, spanning over the parotic processes, the 

 processus ascendens of the supraoccipital bone, and covering the 

 greater part of the latter in this species, so that the pars condy- 

 loidea of the occipital alone projects beyond it when the skull is 

 viewed fi'om above. 



The parietal processes, slightly triangular in a transverse 

 section at their terminal parts, are quite flat at their basal 

 portions and are mere continuations of the median portions of 

 the parietal itself. They have not, as is the case with the 

 majority of the Wall-Lizards in which the facies cranialis is more 

 elevated, the downward!}^ directed ridges set at right angles with 

 their bases, in order to establish the contact with the underlying 

 supraoccipital. 



Jiio Foramen pariefale. (For special remarks on this striking 

 feature refer to p, 29 at the end of the description of cranial 

 characters.) 



