. Bulletins of American paleontology. 48 Bulletin 185. Text-fig. 11.—Morphologic lineaments of Victoriacystis ivilkinsi Gill and Caster, new genus, new species, based on photographs of the holotype. A. Plastron surface. B. Carapace surface. C. Diagrammatic representation of the proximal region, lateral view, showing the hooded overhang of the carapace above the proximal stele, and the corresponding excavation of the plastron to accommodate the exceptionally large and broad proximal stele. Solid lines represent definite margins and sutures. Broken lines are lineaments, in part sutural, in part
. Bulletins of American paleontology. 48 Bulletin 185. Text-fig. 11.—Morphologic lineaments of Victoriacystis ivilkinsi Gill and Caster, new genus, new species, based on photographs of the holotype. A. Plastron surface. B. Carapace surface. C. Diagrammatic representation of the proximal region, lateral view, showing the hooded overhang of the carapace above the proximal stele, and the corresponding excavation of the plastron to accommodate the exceptionally large and broad proximal stele. Solid lines represent definite margins and sutures. Broken lines are lineaments, in part sutural, in part fractures, and possibly in part repre- sentations of margins of plates of the opposite thecal surface. Lateral dotted lines indicate the lateral geniculation of mitrates. The mitrate "triangle" carina of the inner proximal plastron region is also shown in dotted lines. The plate nomenclature is that of Caster (1952; 1954) which has also been applied to Placocystites in the foregoing text-figure 10. The diagonally ruled proximal ("tegmenal") plates, first noted in these Australian specimens, are now known in great detail from American Ordovician E)wploura (1959). Drawing by Anneliese S. Caster. carapace is as seen from above externally or on the inner mold ; the plastron as seen on the outer mold. The plates are identified (with reservation as to homologies) in terms of the plate nomenclature of Caster (1952 ; 1954) . On a "tegmenal" surface, normal in orientation to the plastron, there. 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 Paleontological Research Institution (Ithaca, N. Y. ); Columbia University. Ithaca, N. Y. , Paleontological Research Institution [etc. ]
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