TV oittotofj of the typical Ophidian rrptilcs differs from that of the Ilainrhuuu, in the inure 

 dadoed rib*; in the distinct basi- and su|>cr-occipital* ; in the wpamnpiul forming part of the ear 

 chamber . in the basioeripiul combining with the exoottpiral to farm a single articular condylr for the 

 atlas ; in the oMttatkn at the membranous space between the etongatfd parietal* and the sphenoid . 

 in the rooaUot coalescence at the parietal* with one another ; in the constant confluence of the orbito- 

 spneuoid* with the frontal*, and in the meeting of the orbitosphcnoids below the proantcephalon, upim 

 the upper surface of the preaphenoid ; in the preaenc* of distinct postfrontal*. and the attachment 

 thereto of the aotopterygoids, whereby they form an anterior point of suspension of the lower jaw, 

 through the medium of the pterygoid and tympanic bones ; in the eonnation of the prefrontaU and 

 The trunk may be very long and consist of numerous vertebras, and all trace of locomotivr 

 i may be wanting in the Balrarkta. t. g. in the CWri/uc, as in the typical 



Order LACERTILIA. 



Family Scincoidea. 



Cyclodtu. 



655. The vertebrae of tin- trunk, with the bones of the extremities, of the block Scink 

 of Australia (Cyclodtu *(yr). 



The inferior spine or hypa|>ophysis of the atlas is triangular ; its base supports laterally tin- 

 neural arch of the atlas, and posteriorly the proper centrum of the atlas or ' odontoid process,' 

 whilst anteriorly it form* the lower third of the cup for the occipital condyle ; its apex is pro- 

 longed downwards into a broad compressed spine. The base of the neural arch forms anteriorly 

 the sidea of the articukr cup, and, above this, the neural canal, the aide* of which are notched 

 anteriorly : each neurapophysi* sends off posteriorly two short proceswa, the lower one being 

 the diapophytis, the upper one the iygt|>ophysi* ; the apes of the arch forms a low ridge. 



The axis is a much larger, especially a deeper, vertebra, the neural spine being as long as 

 the haemal one : the sutures which exist in the Monitors between the centrum and odontoid 

 process, and between this and the spine tent down from that process, are obliterated in the 

 CyeloJiu. as in the Iguana -, but the limit* of the odontoid are indicated by the fissure be- 

 tween it* hypapophysis and that sent down from the body of the axis in the Cyclodtu. Thr 

 fore part of the odontoid forms, as in the other sealed reptiles, the back part of the cup for 

 the occipital condyle : a rudimental diapophytis project* from the side of the odontoid. The 

 neural arch of the axis send* off a larger diapophysi* and a posterior sygapophysis on each 

 side, and terminates above in the strong and long compressed spine. The neural and hsemal 

 spine* of the third cervical are a* long as, but lea* broad from before backwards than, those 

 of the axis ; the centrum presents anteriorly a cup answering in form to the ball of the axis, 

 and terminates in a similar ball posteriorly. The diapopbyses are longer than those of the 

 preceding, or even than those of the succeeding lertebtse : the prexygapophyse* are fully 

 developed and look upward*, the posUygapopbyses look downward* : both extend outwards 



T2 



