384 



basipterygoid processes are peculiar in that springing from 

 tlie under surface of the body they are directed bacl.irunU 

 and laterally, they are very broad at their base and together 

 form a triangular area, which in the articulated skull 

 appears between the diverging basitympanic portions of the 

 pterygoids and the basioccipital. The basioccipital articu- 

 Latea with a narrow crescentic area [5] on the upper surface 

 of the arcuate posterior margin of the processes, below 

 this a free surface [9] on the conjoined processes forms 

 with the basioccipital in the articulated skull an arcuate 

 fossa into the sharp margin of which the occipital tendons 

 of the dorso-occipital muscles are inserted. Between the 

 processes and the body on either side is a deep notch into 

 which the pterygoid bones fit [11]. The rostrum is 

 perforated on either side in front of the pituitary region 

 by a carotid foramen [10], the two foramina opening close 

 together on either of the mid line, on the dorsal aspect just 

 a little further forward, are continued anteriorly as grooves 

 on this surface of the bone. Inferiorly the rostrum articu- 

 lates with the pterygoid bones and is from this aspect 

 entirely hidden by them. 



The Entire Skull. 

 (A) Preliminary review [Figs. 40 to 50]. 

 As viewed from above, the side, and in front the follow- 

 ing features are seen. The sagittal suture is continued 

 right forward to the alveolar margin, being only interrupted 

 by the anterior nasal aperture. The bones on either side 

 of the sagittal suture are, from before backwards, the 

 prernaxillae, prefrontals, frontals, and pai iotals (P. Mx., 

 P. Fr., Fr., Par.). The prernaxillae form the most anterior 

 portion of the alveolar margin, which is completed on either 



late with the jugals (.In.) and the-.- with the quadrate- 



