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"Section of shell of Nautilus." -Thomson, 1916

Nautilus Shell

"Section of shell of Nautilus." -Thomson, 1916

"Section of the shell of Nautilus pompilius, showing the septa (s, s), the septal necks (s. n., s. n.), the siphuncle (si, represented by dotted lines), and the large body-chamber (ch)." -Parker, 1900

Chambered Nautilus

"Section of the shell of Nautilus pompilius, showing the septa (s, s), the septal necks (s. n., s. n.),…