348 



ZOOLOGY 



SECT. 



In the skull of the Opliidia (Fig. 088) orbitosphenoidal and 

 alisphenoidal elements are absent, their places being taken by- 

 downward prolongations of the parietals and frontals. In the 

 substance of the niesethnioid are two cartilaginous tracts fFig. 

 981), B, T) which are the persistent trabecula- of the fcetal skull. 

 The intcrorbital septum is absent, and the cranial cavity is 

 prolonged foi-wards to the ethmoidal region. Tiie palatines 

 {PJ) are movably articulated Avith the base of the skull ; as in 



B 



^f7*Pm:c 



Fm^e 



S' '1\ M//.e„; tnXXM \OsD / -'im /W^ /j'/j ^m Fov 



Art 



Fir.. OSS.— Skull of Colubrine Snake (TropidonotUS natrix). A, from above ; B, fi-om below. 



Alt. angular; ..^r/. articular ; Vy,;. ba^<^lK•^il.ii;ll : /j'a basis] Oicnold ; t7(. internal naros ; Core. 

 occipital condyle ; hi. dentary ; Eth. cthnidid ; /-'. frontal ; .F'. post-orljital ; iv).-. Fenestra 

 ovalis ; M. Maxilla; i\'. nasal; 01. exoccipital ; (?.</). ' upraoccipital takina: the jdacc of 

 orbito-sjihenoid ; /'. jiarietal ; /'. . periotic ; /'./'. prefrontal ; f/. palatine ; I'ln.e.. la-emaxilla ; 

 Pt. i)tcrygoid ; 01. exoccipital ; y». quadrate ; SA. supra-angular ; .S'lyit. squamosal ; Ts. 

 transverse ; Yo. vomer ; //, optic foramen. (From Wicdersheim's Comyavalix-t Jdntomn.) 



the Lizards, they are widely seiDaiated from one another, and do 

 not develop palatine plates. They are movably articulated behind 

 with the pter3'goids(7Y), and the latter, through the intermediation 

 of the slender transverse bones (T.s), with the maxilla-. The 

 premaxillffi are very small (in some venomous Snakes entirely 

 absent), and when present usually fused together. The maxillae (3fx), 

 usually short, articulate by means of a movable hin^e-point with 

 the conjoined lacrymal and pre-frontal (/.'/), uhich, in turn, is 

 movably connected with the frontal. The long and slender quadrate 

 (Qu) is freely articulated witli tlie posterior end of the elongated 

 squamosal. The rami of the mandible, likewise long and slender, 



