324 Prof. D. M. S. Watson on 



Separated from the process of the prootie above described 

 by H V-shaped uotch is aiiotlier upstanditig; process, which 

 rises irom the outer surface of the body of the bone, so as to 

 leave a notch which continues the middle groove on the 

 sphenoid and gives exit to the facialis. 



This process touciies, and in adults fuses with, a slender 

 descending process from the parietal, the bar so formed being 

 sepaiated from the hinder border of the upper part of the 

 s])l:enoid by a slit. 



Three other bones occur in the lu-uial cranium of old 

 individuals. The mutual relations of these elements is clear, 

 but their exact position in the skull cannot be determined. 



One of these bones is bilaterall}^ symmetrical, andean only 

 be a su[)raoccipital. It is known to me only from the visceral 

 surface in one vt-ry huge skull. 



It is a small lu-xagonal bone, lightly ossified, but of con- 

 siderable thickness. The dorsal surface has a considerable 

 extension, the smooth endocianial surface being very small. 

 It was undoubtedly separated from all other bones by a great 

 deal of residiuil cartilage. 



The posterior of the two remaining pairs of bones is the 

 first of the series to ossify. 



It consists of an almost square^ vertically placed sheet of 

 bone with a fiat adiuesinl surface. The upper margin of this 

 sheet is turned outward, so that it lies horizontaily. The 

 posterior lateral corner of this rtigion projects as a definite 

 ijrocess of comparatively small aniero-posterior width. 



'i'he vertical part of this bone is pierced near its hinder 

 nnirgin by two small foramina, the anterior and larger of 

 which lies at the upper end of a deep vvell-dt-fined groove. 



The third element is attached to the lower two-thirds of 

 the anterior margin of the vertical p.ut of that just described. 

 It also is a mere sheet of bone standing vfirtically, but is 

 placed neaily transversely in the skull. The inner border 

 is smoothly rounded and cut out into a wide shallow bay 

 rianul the brain-cavity. 



From the middle point of the upper edge of the inner 

 suiface of this bone a special very thin bony spicule arises 

 and runs directly forward parallel to the middle line. 



PaJato-quadrate. — Two ossifications occur in the ))alato- 

 quadrate cartilagt — a quadrate and the bone called hyotnan- 

 dibular by mo.st authors, which has been correctly determined 

 by iStensio as a metapterygoid. 



The (juadrate is a d( ej) slendi i' bone, a birge pait of whose 

 inner surface is covered by the ptei'jgnid, the two bones 



