. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Morphology of Mammal-like Reptiles of Suborder Therocephalia. 251 sent forwards by the basisphenoid (basisphenoidal rostrum); the quadrate rami stretch postero-laterally with a straight outer edge (as is typical for the Therocephalia in contradistinction to the Gorgonopsians, where it is curved) to meet the quadrate. The basioccipital (figs. 25-27) forms the well-developed condyle, and, in a fracture, the processes supporting the basisphenoidal tubera are very well shown; dorso-laterally the exoccipi
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Morphology of Mammal-like Reptiles of Suborder Therocephalia. 251 sent forwards by the basisphenoid (basisphenoidal rostrum); the quadrate rami stretch postero-laterally with a straight outer edge (as is typical for the Therocephalia in contradistinction to the Gorgonopsians, where it is curved) to meet the quadrate. The basioccipital (figs. 25-27) forms the well-developed condyle, and, in a fracture, the processes supporting the basisphenoidal tubera are very well shown; dorso-laterally the exoccipitals support the condyle; the medulla rested on its rather irregular grooved dorsal surface. The basisphenoid forms two widely separated tubera and, anteriorly, forms the deep vertical keel flanked by the pterygoids; the basipterygoid processes are horizontal, flat, and immovable; in a sagittal fracture no trace of a median parasphenoidal process is seen extending dorsally, although both the anterior and posterior borders of the pituitary fossa can be seen; it is, however, possible that the anterior part of the bone Fig. 27. — Theriognathus microps. , labelled "basisphenoid" re- J70?5' Lateral view of the left side of the L bram-case. x ^. presents a parasphenoid indistinguishably fused with it; in a cross-section it is seen that the basisphenoid forms a broad floor for the hind-brain. The pro-otic is only partly exposed and, as far as can be ascertained, agrees with the condition in Notosollasia; it lies against the par- occipital; antero-dorsally, it forms the ventral border of the venous foramen; the foramen for the seventh nerve apparently lies in the usual position; that for the fifth is obscured by the epipterygoid. The epipterygoid, as in all the Whaitsids, is a large flat element with expanded dorsal and ventral ends; its base on the quadrate ramus of the pterygoid is very long and, as it lies lateral to the cavum epiptericum, obscures the foramen fo
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
