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Keywords from Image Description:
Origin of Vertebrates Fig . Fig Skeleton of HeadRegion of Ammoctes Lateral View Ventral View Dorsal View Mucocartilage red soft cartilage blue hard cartilage purple sk skeletal bars position of pineal eye na cart nasal cartilage ped pedicle cr cranium nc notochord All references in this work to Ammoctes or Petromyzon appear to refer