umbilical area造句

• The umbilical area may be partially open, nearly closed or sealed.
• In this order, suture complexity developed by the addition of lobes from the umbilical area, across the flanks, during the life ( ontogeny ) of the animal, and phylogenetically with succeeding genera.
• "Acanthonautilus ", like " Solenochilus ", has an involute, globular shell of few volutions that enlargens with fair rapidity, with prominent lateral spines extending from the umbilical area at maturity.
• Chambers on the umbilical side are subtriangular, each with a triangular folium, or flap, that extends into the umbilical area, folia of successive chambers fuse to form an umbilical plate that is solid or has only rare perforations.
• It is marked by seven strong moderately raised spiral keels that, like the channels that separate them, diminish regularly in width from the periphery to the umbilical area; the last, the eighth, immediately behind the columella, being less distinct and considerably broader than the rest.
• ""'Solenochilus " "', type genus of the Solenochilidae is an extinct cosmopotilian nautilid from the Lower Pennsylvanian to the Lower Permian with a rapidly expanding, coiled globular shell with few whorls, from which prominent spines extend laterally from the umbilical area at maturity . " Solenochilus " is derived from the Upper Mississippian " Acanthonautilus ", principally through evolutionary changes in the siphuncle.