58 ME. C. W. ANDEEWS ON THE SKULL AND 



between the anterior and posterior quadrate facets. Of these, the antero-external (o.f.) 

 is very large, oval in outline, and concave in all directions, but more deeply so from 

 before backward ; its outer edge forms a prominent lip on the lower edge of the 

 squamosal prominence. The other facet (if.) is placed internal and posterior to the 

 last ; in form it is a very elongate oval, the long axis being antero-posterior, in which 

 direction it is deeply concave : it looks outward and downward. The opening of a large 

 pneumatic fossa separates it from the downwardly projecting process of the squamosal 

 and also from the anterior facet. Mesiad of the posterior facet, but separated from it 

 by a narrow flat ledge of bone, is a very deep pocket-like depression, into which open 

 numerous foramina. The most posterior of these seems to be the fenestra ovalis; the 

 others are probably pneumatic. Ventrally the tympanic cavity communicates by wide 

 openings with the anterior tympanic recess and the eustachian canal. 



The squamosal region (Plate XIV., sq.) is deeply concave from before backward, 

 and slightly convex from above downward. Posteriorly it forms the anterior face 

 of the prominent lambdoidal crest ; ventrally, as already mentioned, it is produced 

 downward into a pointed process, which helps to form the outer boundary of the 

 tympanic cavity. Anteriorly its ventral edge is formed by the prominent outer lip of 

 the anterior quadrate facet (o.f.). About 7 mm. above this there is a prominent 

 elongated tuberosity, the long axis of which is directed downward and inward ; this I 

 take to be the zygomatic process (zy.). From its upper end a slight ridge runs upward 

 and backward to the lambdoidal crest (l.r.), and forms the lower boundary of the 

 temporal fossa. Internal to the zygomatic process, and connected with it by a short 

 ridge, is another angular projection, the pretympanic process ; from this also a slight 

 ridge runs upward and backward, but it soon dies away without reaching the 

 main temporal ridge. 



As might be expected from the great massiveness of the mandible, the temporal 

 fossse are very large and deep. Their lower opening is bounded posteriorly by the 

 zygomatic, anteriorly by the postorbital process (p.orb.p.), which approach to within 

 17 mm. of each other. The fossae are much deeper than broad, and greatly constrict 

 the side of the cranium. Superiorly they are bounded by the temporal ridges, which, 

 as above mentioned, run upward and backward from the zygomatic process till they 

 meet the lambdoidal crest (l.r.), with which they are confluent for 28 mm. Leaving 

 the lambdoidal ridge, they sweep forward, first towards the middle line, then outward, 

 terminating anteriorly on the upper surface of the postorbital process. On the roof 

 of the skull the fossa? are separated one from another by an interval of about 

 12 mm. only. 



On the side of the cranium, immediately below the constriction caused by the 

 temporal fossae, and about on the same level as the quadrate facet, there is a deep 

 infundibuliform depression, at the bottom of which the trigeminal foramen opens. 

 This depression is marked off from the orbit by a ridge which runs upward and 



