THE SKULL. 



55 



Caudally there appear in the ventral view the foramen 

 magnum (a), occipital condyles (), and jugular processes (c\ 

 In front of the jugular processes the two tympanic bullae (d] 

 form prominent features, with the mastoid process (e}, the 

 stylomastoid foramen (_/), and the external auditory meatus 



FIG. 41. SKULL, VENTRAL VIEW. 



I, occipital bone; 2, temporal; 3, sphenoid; 4, presphenoid ; 5, frontal; 6, malar; 

 7, vomer; 8, palatine; 9, maxillary; 10, premaxillary. a, foramen magnum; 6, 

 occipital condyles; c, jugular process; d, tympanic bulla; e, mastoid process; f, stylo- 

 mastoid foramen; g, external auditory meatus; h, jugular foramen; i, styliform proc- 

 ess ; ji groove for Eustachian tube; A, foramen ovale; /. foramen rotundum; m, 

 pterygoid process of sphenoid; n. perpendicular plate of palatine; o, choanae or pos- 

 terior nares; /. zygomatic arch; q. cranial end of posterior palatine canal; r, pala- 

 tine grooves; s, foramina incisiva or anterior palatine foramina; t, opening of ptery- 

 goid canal. 



(g) on their lateral surfaces. All these structures have been 

 described. The tympanic bullae (d) are placed with long axes 

 directed craniomediad, so that they converge toward their 

 cranial ends. At the caudomedial angle of each bulla is the 



