TEICLEIDUS SEELEYI. 



lol 



for the reception of the pituitary body {pit.foss.). The postero-external angles of the 

 posterior portion of the bone are obliquely truncated by small facets [pt-f.^) for union 

 with the anterior ends of the basisphenoid processes of the pterygoids. The upper 

 anterior angles of the body of the bone bear a pair of facets (/., in text-fig. 73, A) 

 looking upwards and a little outwards, which, judging from comparisons with some 

 recent forms, united with the lower end of the anterior prolongation of the prootics. 

 The posterior surface of the pituitary fossa is perforated on either side by a large 

 foramen for the internal carotids {i.c.f.); from the outer anterior border of each of 

 these openings a sharp crest runs outwards and forwards on the cranial surface, 



Text-fijr. 73. 



Basioccipital, basisphenoid, and parasplienoid of Trideidus seeleijl : A, from above ; B, from right side. ' 



(E. 3539, nat. size.) 

 6s.., basisphenoid ; ea-o./., surface for uiiiou with the exocoipital ; /., in fig. A facet for (?) lower end of 

 prootic, in fig. B facet for pterygoid ; i.c.f., internal carotid foramen ; oc.c, occipital condyle ; 

 pas., paraspheuoid ; pit.foss , pituitary fossa ; pt.f., facet for posterior ramus of pterygoid ; pt.f.^, fact-t 

 for process of pterygoid ; pt.f.^, facet for inner border of palatal ramus of pterygoid ; v.e.p., lower 

 cylindrical processes of basisphenoid. 



apparently defining the outer side of the pituitary fossa. External to this ridge and in 

 front of the carotid foramen the sides of the bone are produced into short wing-like 

 processes, terminating on facets (/., in text-fig. 73, B), looking outwards and forwards, 

 probably for union with the pterygoids, though this is not certain. The basisphenoid 

 terminates antei'iorly in two short vertically-compressed processes [v.c.p.) ending in 

 transversely elongated facets for union with the bone or cartilage of the presphenoid 



