. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. SOUTHERN AFRICAN RAJIDAE (CHONDRICHTHYES, BATOIDEl) 63 case of Rhinobatos halavi, Rhynchobatos djiddensis and Trygon kuhlii (El-Tourbi & Hamdy 1959), the abducent nerve enters the orbit through the pro-otic foramen in rajids. The posterior border of the orbital region is marked dorsally by the small postorbital process. It is most prominent in Bathyraja smithii (Fig. 49 A). On each side of the neurocranium, at its posterior end, are the auditory capsules, between which is the parietal depression
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. SOUTHERN AFRICAN RAJIDAE (CHONDRICHTHYES, BATOIDEl) 63 case of Rhinobatos halavi, Rhynchobatos djiddensis and Trygon kuhlii (El-Tourbi & Hamdy 1959), the abducent nerve enters the orbit through the pro-otic foramen in rajids. The posterior border of the orbital region is marked dorsally by the small postorbital process. It is most prominent in Bathyraja smithii (Fig. 49 A). On each side of the neurocranium, at its posterior end, are the auditory capsules, between which is the parietal depression (endolymphatic fossa of El-Tourbi & Hamdy (1959)). This is similarly situated in all rajid species and contains two pairs of foramina leading to the auditory capsules. The anterior pair are the endolymphatic foramina and the posterior pair, which lead directly to the perilymphatic cavity, are the perilymphatic foramina. At the posterior edge of the lateral surface of the auditory capsule is the articular facet of the hyomandibular cartilage, which is in the form of an elongate, slightly concave groove, running antero-dorsally. It is bordered dorsally by a shallow depression, the postorbital groove, which contains the posterior region of the postorbital sinus. This vessel passes through the jugal arch to become the anterior cardinal vein (jugular vein of Heintz (1962)) at the junction with the posterior cerebral vein (O'Donoghue & Abbott 1928). The jugal arch links the protuberance of the hyomandibular facet to the posterior region of the auditory capsule. Its size and position (Figs 49-54) seem to bear. 2!^ES. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original South African Museum. Cape Town : The Museum
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
