CRANIAL CHARACTERS OF LACERTA JACKSONI. 29 



atigle to its hoi-izontal plane as in the male, but is less expanded 

 at its base, immediately beliind the constriction between the 

 nerve-holes. 



The Nasal bones, which, owing to extensive incrustation, in 

 the male specimen were described as ill-defined, are here quite 

 distinct in their entirety. Anteriorly their proximal processes, 

 between which the nasal process of the praemaxillary is wedged, 

 extend to the middle of the latter. Their lateral margins, shorter 

 than those forming the median suture and moreover less decidedly 

 linear, are parallel to each othei'. Their posterior edges, scale- 

 like in shape, and imbricating in a similar manner on the fi-ontals, 

 are characteristic in having from 2 to 3 pointed lobes, of which 

 the median ones are the longest, so as to become a fork into the 

 prongs of which the median process of the frontal penetrates. 



The Prcefrontals also ara more clearly defined in the female. 

 They show their posterior frontal processes, which constitute the 

 margo orbitalis anteriorly, to be spurs which extend nearly as far 

 back as the suture between supraocularies 2 and ?>. 



The Jugulars do not dift'er from those of the male. 



Occipital Segment. — The tSujn'aoccipital is united along its 

 entire upper margin with the posterior edge of the parietal bone. 

 The processus ascendens, so tolerably well developed and forming 

 the sole support of the parietal in the male, is quite rudimentary 

 here and reduced to a tubercle only. It is lower even than are the 

 a.pophysial elevations of the epiotic portions of the bone, and, 

 together with the epiphysial cartilaginous spine and a small 

 portion of the membi'anous cranium, is laid bare and quite un- 

 protected by the paiietal. The sutures between the supraoccipital 

 and the pleuroccipitals are perfectly distinct. The foramina 

 retrofrontalia, in consequence of this extended transverse con- 

 nection between the parietal and the supraoccipital, are more 

 markedly reduced than in the male. 



The Basioccipitcd and Basis2)henoid are not fused as in the male, 

 the suture between them showing distinctly (text-fig. 7, p. 27). 



The Squamosals are flatter and less curved downwards than in 

 the male. 



The Vomer ^^Icties are more loosely united than in the male ; but 

 the Palatines, though more distinctly united, have their sagittal 

 ridges imperfectly developed as compared with those of the 

 male. The stolci palatince are also shallower in this skull. 



Mandible. — This consists of the six elements, of which each 

 ramus is composed in all immature Lizards as pointed out 

 by Siebenrock, the supra-angulare and articulare being not yet 

 united by fusion. 



On the Absence of the Foravien parietale. 



After first ascribing the absence of the orifice for the pineal 

 eye in the skull of the male to purely pathogenic causes, or to 



