SKULL 



109 



the cranio-vertebral boundary is in a similar relative position, in 

 spite of differences of form in this region. The cerebro-nasal 

 axis, which is horizontal in Amphibians, becomes more or less bent 



Sup. olf. cart. 

 Dorsal nasal fenestra 



Lat. nasal fenestra 



Orb. nas.Jissurt 

 Spheneth. carl 



Max. proc.*~ 



Pituitary fenestra 



Asc. proc. s 

 of pal. quad. 



Columella. 



Optic fenestra 



FICJ. 80. SKULL OF AN EMBRYO Lacerta agilis, 47 MM. IN LENGTH. A, 

 DORSAL, AND B, VENTRAL VIE\V. C, LOWER JAW AND HYOBRANCHIAL 

 SKELETON, FROM THE VENTRAL SIDE. 



(After Gaupp, from a wax model by Ziegler x ^.) Cartilage, blue ; 1'eplacing bones, 



gray ; investing bones, ytUow. 



downwards in front of the interorbital region, and thus causes 

 various modifications as regards the relations of the nasal and 

 cranial cavities (cf. Fig. 90). 



