SKELETON. 



S7i 



temporal bones._ The orbit is roofed by a series of small bones, of 

 which the anterior and posterior are respectively known as pre- and 

 post-frontal. 



On the floor of the adult skull there is a large basal bone, composed 

 of fused occipital and sphenoidal elements, and continued forward as a 

 slender bar (parasphenoid). This bone gives off two stout processes, 

 the basipterygoid processes, which articulate with the pterygoids. Each 



Fig. 248. — Side view of skull of Lacerta. — After W. K. Parker. 



px., Premaxilla; mx., maxilla; /., lachrymal;/, jugal ; t.fia., 

 transpalatine ; epg., epipterygoid ; pg., pterygoid; bpg., basi- 

 pterygoid; b.o., basioccipital ; >/., quadrate; oc.c, occipital 

 condyle ; sq., squamosal ;pr.o., pro-otic ;pt.o., postorbital ; sii. 

 sts., su prate mporals ; ps. t presphenoid (the optic nerve is seen 

 issuing in front of the end of the reference line) ; fi.e., mes- 

 ethmold ; s.ob., supraorbitals ; pf., prefrontal ; «., nasal ; ar. t 

 articular; ag., angular; sag., surangular ; cr., coronary; d., 

 dentary. 



pterygoid is connected posteriorly to the quadrate bone of the corre- 

 sponding side, and anteriorly with the palatine. From the union of 

 pterygoid and palatine, a stout os transversum or transpalatine extends 

 outwards to the maxilla. In front of the palatines lie the small vomers, 

 which, in their turn, articulate with the premaxilla and maxilla, both of 

 which are furnished with small pointed teeth. In the posterior region 

 of the skull we have still to notice the large ex-occipitals with which the 

 opisthotics are fused, and which are continued into the conspicuous 

 parotic processes. The lateral walls of the brain-case are largely formed 



