124 



COMPARATIVE ANATOMY 



are firmly united with one another. The higher we pass in 

 the Mammalian series, the more does the former come to lie below 

 instead of in front of the latter, the facial skeleton becoming 

 proportionately small as contrasted with the large cranial portion 



FIG. 90A. LONGITUDINAL VERTICAL SECTIONS THROUGH THE SKULLS OF A, 

 Salamandra macnlosa. B, Testudo yrwca, AND C, Corvux corone, TO SHOW THE 

 RELATIONS BETWEEN THE CRANIAL AND NASAL PORTIONS. 



of the skull, and the reduction of the angle between the basi- 

 cranial and vertebral axes being carried still further than in Birds 

 (cf. Fig. 90). 



The base of the skull is mainly preformed in cartilage (Fig. 91), 

 and is but little interrupted except for the passage of vessels and 

 nerves. It consists of basioccipital, basisphenoidal and ethrnoidal 



