374 H. L. KESTEVEN. 



|8] is continued up the medial aspect of the hinder border 

 of the alispheuoid plate. The posterior margin of the body 

 is free and forms the posterior boundary of the false roof 

 (marijo temporalis) [15], the lateral border is divided into 

 s<|u;imosal [9] and postfrontal [10] segments, anteriorly the 

 bone articulates with the frontal [11]. The alisphenoid 

 process is a triangular plate of bone, its anterior margin 

 merges above with the orbito-sphenoid crest. The apex 

 articulates with the epipterygoid process of the pterygoid 

 bone being deeply notched to receive that process (iticisura 

 pberygoidea) [13]. The free portion of the posterior margin 

 bounds the foramen ovale [14], and above this is a small 

 facet which articulates with the prootic (fades prootica) 

 [12]. 



The Postfrontal (Os postfrontal) [Fig. 17] presents 

 frontal [1], parietal [2], squamosal [3], quadra to- jugal [4], 

 and jugal [5] borders for articulation with those bones, and 

 by an arcuate orbital margin [6] it bounds the postero- 

 superior one third of the orbit. Continued up and slightly 

 backwards from the vertical segment of the orbital margin 

 is a rounded ridge which divides the inner surface into 

 lachrymal [7] and temporal surfaces [8], the one in contact 

 with the lachrymal gland and the other walling in the tem- 

 poral fossa. 



The Jugal (Os jugale) [Pig. 18 and 19], of irregular form, 

 presents margins for articulation with postfrontal [1] 

 quadrato- jugal [2] and maxilla [3]. Its anterior margin [4] 

 bounds the postero-inferior segment of the orbit, anil oppo- 

 site this is a free border which forms the anterior margin 

 of the zygomatic sinus (manjo ::\}<jomatiea) [5]. Anteriorly 

 the body bears a medially projecting plate of bone ( processus 

 pterwjoideus) [6] which is the homologue of the ectoptery- 

 goid, and like that bone serves to connect the maxilla and 

 pterygoid [9], there is however no gap between it and the 



