THE ENTIKE SKULL 467 



terior nares, through which the fossa communicates directly with 

 the nasal chamber. It is freely open behind. Its sides, formed by 

 the palatines and the pterygoids, are parallel and slope upward and 

 inward from their free, narrow, and rounded lower edges to pass 

 without a distinct break into the roof of the fossa. A well-marked, 

 rounded, longitudinal ridge occupies the centre of the roof and is 

 embraced in front by the diverging posterior ends of the vomer. This 

 ridge is on the under surface of the presphenoidal body and separates 

 the palatines and pterygoids of the two sides. The line of separation 

 is the lower prespheno-palatine suture and the prespheno-pterygoid 

 suture, at the junction whereof is seen the transverse pterygo-palatine 

 suture. A small additional piece of the under surface of the pre- 

 sphenoidal body appears also on each side of the median ridge and 

 usually between the palatines. The lower lateral edges terminate 

 behind in the hamular processes of the pterygoids, which are directed 

 downward and backward and support the aponeurosis of the tensor 

 palati muscle. Above the roots of these processes the posterior edges 

 of the lateral walls slope upward, backward, and outward and become 

 continuous with the rest of the base of the skull in front of the 

 auditory bullse. They are hollowed to form the oblong external 

 pterygoid fossae which afford attachment to the internal pterygoid 

 muscle. On the outer side of these fossae are the external pterygoid 

 processes. 



Behind the external pterygoid fossa on each side is a slightly con- 

 cave area known as the scaphoid fossa, from which arise the levator 

 and tensor palati muscles. The scaphoid fossa passes outward and 

 backward over the front end of the auditory bulla into the Eustachian 

 opening, which lodges the Eustachian tube and the palatal muscles. 

 On the inner side, and anterior to the scaphoid fossa, at the edge of 

 the pterygoid bone, is seen the slit-like posterior opening of the Vidian 

 canal for the Vidian nerve. 



The triangular area lying between the two scaphoid fossaa, con- 

 tributed by the basisphenoid, passes in front into the middle ptery- 

 goid fossa and behind into the space between the bullas. It is slightly 

 convex transversely, and affords attachment to the posterior wall of the 

 pharynx. Lateral to the scaphoid fossa is the foramen ovale, which 

 transmits the inferior maxillary branch of the trigeminal nerve. In 

 front of this foramen is the foramen rotundum for the superior maxil- 



