200 D. DAVIDSON BLACK 



anterior extremity of the ridge a small vessel is given off and 

 passes downwards through a median foramen to the orbit. This 

 vessel is an azygos ophthamic artery. Immediately after the 

 ophthalmic branch is given off, the main vessel turns backward 

 upon itself and courses a short distance in this direction before 

 passing upward through the dura as the single median artery 

 already noted. There is no appearance whatever of anterior or 

 posterior clinoid processes. 



On either side of the median ridge the third and sixth nerves 

 pass forward beneath the dura to the median foramen mentioned 

 above to gain the orbit. Slightly more laterad the ophthalmic 

 division of the fifth nerve passes forward to the same destina- 

 tion. Accompanying the latter is a small nerve which may (?) 

 represent the trochlear though subsequent dissection failed to 

 identify it definitely. 



The spheno-temporal suture may be clearly made out, extend- 

 ing outward from the region of the carotid canal. Anteriorly 

 another suture may be made out passing parallel to the posterior 

 boundary of the anterior fossa, and marking the line of union 

 between the frontal element and the great wing of the sphenoid. 



Below the posterior end of the median crest, between the enter- 

 ing carotid arteries and behind the point of their junction, there 

 is found a small pit in the basi-sphenoid into which are prolonged 

 a few fine processes from the dura. This depression was not 

 apparent before removal of the dura. Further examination 

 showed that the fornix pharj'^ngis was situated immediately be- 

 low this pocket. In fact it marks the site where normally the 

 pituitary body should be lodged. Although no pituitary tissue 

 could be identified, I am inclined to view this pit as a remnant 

 of Rathke's pouch. 



Posterior fossa. In the posterior fossa the occipito-temporal, 

 the parieto-occipital and the parieto-temporal sutures can readily 

 be made out. The foramina for the exit of the nerves in this 

 region presented no peculiarities. 



