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. fissure 

 Spheneth. cart 



Max. proc. 



Pituitary fen 



Asc. proc. x 

 of pal. quad. 



ColumeUa. 



Optic fenest 



ParaquacL 



Squamosal 



Aud. caps. 



Tect. synot. >, o Endolymph 



I I * 



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

 DORSAL, AND B, VENTRAL VIEW. C, LOWER JAW AND HYOBRANCHIAL 

 SKELETON, FROM THE VENTRAL SIDE. 



(After Gaupp, from a wax model by Ziegler x J.) Cartilage, blue ; replacing bones, 

 gray ; investing bones, yeHoic. 



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). 



