. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. THE MORPHOLOGY AND RELATIONSHIPS OF A CROCODILIAN 305 In recent crocodiles the pterygoids also contribute to the secondary palate and are hollowed out behind the palatines and between the pterygoid flanges so that the narial tubes are continued posteriorly. The ridges on the body of the pterygoids of Orthosuchus mark the position of the choanae in eusuchians (Fig. 34). A transitional stage between these is seen in the mesosuchian Theriosuchus (Joffe 1967) where the internal nares lie in a depression
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. THE MORPHOLOGY AND RELATIONSHIPS OF A CROCODILIAN 305 In recent crocodiles the pterygoids also contribute to the secondary palate and are hollowed out behind the palatines and between the pterygoid flanges so that the narial tubes are continued posteriorly. The ridges on the body of the pterygoids of Orthosuchus mark the position of the choanae in eusuchians (Fig. 34). A transitional stage between these is seen in the mesosuchian Theriosuchus (Joffe 1967) where the internal nares lie in a depression which is walled laterally by the pterygoids and roofed by the palatines. The prefrontal of Orthosuchus forms an internal process which extends down towards the palate. In living crocodiles this process unites with that from the other side in the midline, and also with the palatine and pterygoid. A similar process occurs in Pelagosaurus British Museum (Natural History) No. 32599. w. 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
