. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. BRAINCASE, BASICRANIAL AXIS, MEDIAN SEPTUM IN THE DINOCEPHALIA 2 29 Between the lower edge of the prootic and the fenestra ovalis lies the opening of the Vllth cranial nerve. In sagittal section (C) it can be seen that the braincase floor is formed by the exoccipital, basioccipital and prootic, with the foramen for the Xllth, the jugular foramen and the internal auditory meatus lying at floor level. Piercing the ascending process of the prOotic is the foramen for the VIth nerve. Behind the prootic-su
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. BRAINCASE, BASICRANIAL AXIS, MEDIAN SEPTUM IN THE DINOCEPHALIA 2 29 Between the lower edge of the prootic and the fenestra ovalis lies the opening of the Vllth cranial nerve. In sagittal section (C) it can be seen that the braincase floor is formed by the exoccipital, basioccipital and prootic, with the foramen for the Xllth, the jugular foramen and the internal auditory meatus lying at floor level. Piercing the ascending process of the prOotic is the foramen for the VIth nerve. Behind the prootic-supraoccipital bar lies the slit-like trigeminal fenestra. Behind this the sidewall of the braincase, here formed by the prootic, is hollowed out and in this hollow the flocculus was housed. In (D) the occipital plate is seen in lateral view and shows the slit-like trigeminal fenestra bounded anteriorly by the prootic and supraoccipital and the fenestra ovalis bounded by a rim formed by the opisthotic. 11701 Criocephalus sp. (Fig. 27). Fig. 27. Criocephalus sp. 11701 x £. Sagittal section through the skull cap showing the pineal tube. A sagittal cut through this skull-cap shows the constituent bones to be of cancellous nature and the fusion of these spongy bones has obliterated nearly all traces of the original sutures between them. The parietal tube is curved and lies parallel to the midline of the occiput and the curvature of the dorsal surface of parietal and frontal. It is very long— 185 mm, the antero-posterior diameter varies from 9 to 14 mm. 12046 Criocephalus sp. (Fig. 28) A sagittal section cut through a badly weathered skull-cap shows the great thickness of the parietal bone with the parietal tube penetrating this bone. The tube measures 240 mm in height and the diameters vary from 15 to 20 mm. 12066 Criocephalus sp. (Fig. 29) A sagittal section through this skull-cap shows the limits of the constituent bones, although they are spongy. The
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
