Tusk shell

Class of shelled marine molluscs

Scaphopoda (from Ancient Greek σκᾰ́φης (skáphēs) 'boat' and πούς (poús) 'foot') is a class of shelled marine molluscs (invertebrates within the phylum Mollusca), whose members are known as scaphopods and commonly called tusk shells or tooth shells. They have a worldwide distribution and are the only class of exclusively infaunal marine molluscs. Shells of species within this class range in length 0.5–18 cm (0.20–7.09 in), with Fissidentalium metivieri being the longest.

From Wikipedia, under CC BY-SA. More on occurri.