14 TEETIAET YEETEBEATA OE THE EATtTM. 



for tlie attachment of powerful muscles. Beneath the orbit th'e jugal bar is narrower 

 from above downwards, but it is considerably thickened ventrally and bears several 

 strong ridges. Posteriorly it turns upwards and widens out to some extent, meeting 

 the zygomatic process of the squamosal in a long and nearly straight horizontal suture. 

 The posterior angle of the jugal extends well back behind the anterior border of the 

 glenoid surface, of which it may even help to form a part at the outer border. 



The palatines [pi-) form the greater part of the hinder region of the palate, as 

 well as of the side-walls of the nasal canal and of the mesopterygoid fossa. The 

 union of their palatine plates with the maxilla is nearly transverse in front, and 

 in or near the suture there is a pair of small posterior palatine foramina (PI. II. fig. 1, 

 pp-f-\ to which reference has been made above. The anterior end of the palatines is 

 opposite the posterior column of m. 2 in the adult skull : behind this the maxillo- 

 palatine suture runs backwards and slightly outwards. The posterior border of the 

 palate is opposite the hinder end of m. 3 : it is greatly thickened and on either side 

 of the median suture there are two roughened ridges directed forwards and outwards. 

 Behind the palate the ventral edges of the vertical plates of the bones are greatly 

 thickened and deeply notched externally, the notch forming the greater part of the 

 posterior foramen (PI. II. fig. 1, m.f.f.) which has already been described in speaking of 

 the maxilla. A little behind this the palatines join the pterygoids (PI. II. fig. 1,^^.), 

 which form only a comparatively small portion of the descending plates which 

 bound the mesopterygoid fossa. From the ventral edge of the plate the palato- 

 pterygoid suture runs first forwards and upwards, then directly upwards to the 

 lasis cranii, which is overlapped and embraced by the upper edges of both palatines 

 and pterygoids. The palatines also form the side-walls of the posterior portion of 

 the nasal canal, and appear on the inner wall of the orbits above the alveolar mass 

 of the maxilla, with which they unite in suture behind, and from which they are 

 separated by the orbito-nasal foramen in front. The relations of these bones to one 

 another and to the surrounding structures can be best understood by examining a 

 skull of Bendrohyrax (Procavia) dorsalis, in which the sutures all remain open. 

 The upper edge of the orbital plate of the palatine must have united with the orbito- 

 sphenoid, but the suture cannot be made out ; indeed all the boundaries of the 

 orbitospheuoid and alisphenoid are obscure, partly because these bones are very 

 thin and greatly cracked. 



The pterygoids {pt.) form only the posterior part of the deep vertical plates which 

 enclose the mesopterygoid fossa. The suture between them and the palatines in 

 front has already been referred to. Their ventral border is thickened and convex : 

 posteriorly they end in a slightly prominent angle (see PL I.), above which the 

 posterior border of the bone is very thin. The upper edge of the bone unites 

 with the basisphenoid and runs high up on the side of that bone into the opening 

 lying between it and the glenoid surface of the squamosal, an opening doubtless 



