14 
TEETIARY VEETEBRATA OF THE FATtM. 
lor Il)(' atlachiTicnt of ]) 0 \vcrful muscles. Beneath the orbit the jugal bar is narrower 
(Voni above downwards, but it is consideraLly thickened ventrally and bears several 
sti’ong ridges. Posteriorly it turns upwards and widens out to some extent, meeting 
tlie zygomatic process of the squamosal in a long and nearly straight horizontal suture. 
'J'he posterior angle of the jugal extends well back behind the anterior border of the 
glenoid surface, of wliich it may even help to form a part at the outer border. 
I'lie liolatines 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 siiture there is a pair of small posterior palatine foramina (PI. II. tig. 1, 
]>}>■/.), to which reference has been made above. The anterior end of the palatines is 
op])osite the posterior column of m. 2 in the adult skull : behind this the maxillo- 
j)alatine 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 rougliened 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 
])osterior foramen (PI. II. fig. 1, m.p.f.) which has already been described in speaking of 
the maxilla. A little behind this the palatines join the pterygoids (PI. II. fig. I,yj/.), 
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 upwaards to the 
hasis cj'anii, 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 Uendrohyrax {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 wdiich 
enclose the meso{)terygoid 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 ])rominent angle (see PI. 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 np on the side of that bone into the opening- 
lying between it and the glenoid surface of the squamosal, an opening doubtless 
