120 ON THE VEKTEBRATE SKULL. 



to a small extent, to the formation of the two occipital condyles. 

 In the adult skull the basi-occipital anchyloses completely with 

 the ex-occipital, on the one hand, and with the next bone of the 

 basi-cranial axis on the other, so that the saw must be called to 

 our aid in order to demonstrate the bone. 



Fig. 5o. — Cranio-facial axis and lateral elements of the superior arches (as in Fig. 52), with 

 the pterygoid bones, and without the vomer, viewed from below. — c, jiuTction of the 

 basi-sphenoid and presphenoid with the internasal cartilage ; C.S., cornua sphenoidalia, 

 or bones of Berlin. 



From the synchondrosis a to the point b, in even so young 

 a skull as that here represented, the basi-cranial axis is formed 

 by one continuous ossification, the Basi-sphenoid bone, excavated 

 superiorly (Figs. 50 and 52) by a saddle-shaped cavity, the sella 

 turcica, which lodges the pituitary body, — an organ of no great 

 physiological moment, so far as we know, but of first-rate mor- 

 phological significance. 



On each side of the hinder part of the sella turcica, the 

 basi-sphenoid presents a groove for the internal carotid artery, 

 and this groove is completed in front and externally, by tin 

 osseous mass, tapering from behind forwards, the lingula 

 sphenoidalis, which lies between the basi-sphenoid and ali- 

 sphenuid. At the front part of the sella, separating it from the 



