Nautilus shell
Fantastic Monday
Smile on Saturday
Shades of Brown
Nautiluses are the sole living cephalopods whose bony body structure is externalized as a planispiral shell. The animal can withdraw completely into its shell and close the opening with a leathery hood formed from two specially folded tentacles. The shell is coiled, aragonitic, nacreous and pressure-resistant, imploding at a depth of about 800 m (2,600 ft). The nautilus shell is composed of two layers: a matte white outer layer, and a striking white iridescent inner layer. The innermost portion of the shell is a pearlescent blue-gray.
Nautilus shell
Fantastic Monday
Smile on Saturday
Shades of Brown
Nautiluses are the sole living cephalopods whose bony body structure is externalized as a planispiral shell. The animal can withdraw completely into its shell and close the opening with a leathery hood formed from two specially folded tentacles. The shell is coiled, aragonitic, nacreous and pressure-resistant, imploding at a depth of about 800 m (2,600 ft). The nautilus shell is composed of two layers: a matte white outer layer, and a striking white iridescent inner layer. The innermost portion of the shell is a pearlescent blue-gray.