. Bulletins of American paleontology. Alaskan ammonites, Pt. II: Westermann 121. D (mm) Text-fig. 40. — Scatter with growth lines for relative umbilical width (U:D) of Witchcllia sutncroidfs, n. sp., holotype (H) and catalogue or localifj' numbers of other specimens indicated, all from the PscudociJoccras zonule of Wide Bay. Note that the mature phragmocone (dots and solid lines) varies from 26 to 38% U, resembling the IV. sutneri 'plexus' and 'Gelasinites' (Text-fig. 39). At 80-100 mm diameter, tlie principal ribs become more nu- merous by continuation of the primaries into single strengthene
. Bulletins of American paleontology. Alaskan ammonites, Pt. II: Westermann 121. D (mm) Text-fig. 40. — Scatter with growth lines for relative umbilical width (U:D) of Witchcllia sutncroidfs, n. sp., holotype (H) and catalogue or localifj' numbers of other specimens indicated, all from the PscudociJoccras zonule of Wide Bay. Note that the mature phragmocone (dots and solid lines) varies from 26 to 38% U, resembling the IV. sutneri 'plexus' and 'Gelasinites' (Text-fig. 39). At 80-100 mm diameter, tlie principal ribs become more nu- merous by continuation of the primaries into single strengthened secondaries while the others become reduced. The last wliorl of large shells bears strong, mostly simple, rectiradiate, projected to somewhat rursiradiate costae, resembling large Euhoploceras. This strong ornament is usually retained up to the end of the body chamber, with the exception of the more involute and compressed variant where it becomes obsolete. All body chambers retain the striking bisulcate-tricarinate 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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