SKULL — REPTILES 



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the former bounding dorsally a large epioptic fenestra, and a metoptic fenestra 

 arises by the coalescence of the foramina for nerves III and IV, distinct in 

 earlier stages. The prootic pillar is connected by a bar with the otic capsule 

 above the fifth nerve: A paraseptal cartilage connects the supraseptal plate 

 with the nasal capsule which has a single concha. 



The mandibular arch arises as a continuum, its upper part being largely 

 quadrate with pterygoid and epipterygoid processes (fig. 172). The hyoid 



Fig. 172. — Chondrocranium and early bones of Sphenodon; upper figure (Howes 

 and Swinnerton, '01) earlier; lower (Gaupp, '05) a little later; cartilage stippled, bones 

 lined; an, angulare; ap, antorbital plate; c, coronoid; ca, carotid foramen; d, dentale; 

 ec, extracolumella; ep, epipterygoid; /, frontal; fe, epioptic fenestra; h, hyale; ios, 

 interorbital septum; j, zygomatic; mx, maxilla; n, nasal; nc, nasal capsule; oc, otic 

 capsule; pi, palatine; po, postorbital; pof, postfrontal; pp, parotic process; pq, ptery- 

 goquadrate; pt, pterygoid cartilage; plb, pterygoid bone; q, quadrate; qj, quadratojugal; 

 sa, surangulare; si, sphenolateral; sp, splenial; sq, squamosal; ssp, supraseptal plate; 

 55, suprastapedial; t, transversum; v, vomer; z, zygomatic; II— V, 2-4, nerve exits. 



arch at first is in continuity with the stapes, its basal part later forming the 

 extracolumella. The lower parts of the hyoid of the two sides are connected 

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