Description:

 

Marine molluscs with a tapering, tubular, slightly curved tusk-like shell, that is open at both ends. The large end remains anchored in the sand by a cone shaped foot. Influent and outfluent streams take place at the narrow end.

The drawing of this thin shell, near bottom of page, shows its highly retractile, slender ceptacula. Like sticky fingers, secretions on the tips of the ceptacula pick up food particles for transfer to the mouth (See Anatomy & Function).

About 350 species are known, most found in 6 meters or more of water, with a few species, only, found on shore. Cadula shells are typically 4 mm in length, whereas Dentalium shells up to 150 mm have been found off shore of Japan. Fossil species of Dentalium up to 300 mm, with a 30 mm diameter, are known. The shells are widely used for jewelry and are often massed in the beaded portions of  American Indian clothing decorations.

 

Dentalium elephanteum (Linnaeus, 1758)
Elephant Tusk, 6.5 cm
Philippines

Drawing of the common tusk shell,
Dentalium vulgare (da Costa, 1778)