132 THE SKULL. [chap 



through which a branch of the external carotid artery 

 (middle meningeal) enters the brain-cavity. 6 and 8. Th< 

 foramen lacerum medium basis cranii and the foramei 

 lacerum posterius have the same functions and relation as 

 in the Dog. 7. Between these two the periotic has th< 

 conspicuous meatus auditorius internus on its inner sid< 

 The depression above this, for the lodgment of the floe 

 cuius, is distinctly seen in fcetal human skulls up to the 

 time of birth, but it afterwards becomes gradually oblit< 

 rated. 9. The condylar foramen perforates the exoccipital 

 as in the Dog ; and lastly (10), the foramen magnum hi 

 the same general subcircular form, and is bounded by th< 

 same bones, but differs greatly in direction, its plane looking 

 mainly downwards instead of backwards. 



The nasal cavities differ chiefly from those of the Dog in 

 their shortness and greater vertical height. In their inner 

 wall, the descending median plate of the vomer (Vo) is 

 much more developed. The pterygoids (Pt) are extended 

 vertically, are narrow from before backwards, end below in 

 a marked " hamular " process, and soon ankylose with the 

 pterygoid plates of the alisphenoid anteriorly, but posteriorly 

 are separated from them by a well-marked "pterygoid 

 fossa." l The palatines (PI) and maxillae (Mx) are short 

 from before backwards. The premaxillae (PMx) are small 

 and early ankylosed with the maxillae. 2 The nasals (Na) 



1 The pterygoid, not being recognised as a distinct bone, is commonly 

 described \n works on human anatomy as " the internal pterygoid plate 

 of the sphenoid ; " the pterygoid process of the alisphenoid being the 

 '* external pterygoid plate." 



2 The premaxilla is a distinct bone in the human foetus, but is covered 

 on its external or facial aspect by a process of the maxilla, which extends 

 over it towards the middle line, and becomes completely fused with it 

 before birth, so that no trace of the maxillo-premaxrlary suture is ever 

 seen on the outer side of the face. On the inner and palatal aspect of 



