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"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.),…

The modern Pearly Nautilus; the animal occupies the living chamber of the sectioned shell.

Chambered Nautilus

The modern Pearly Nautilus; the animal occupies the living chamber of the sectioned shell.