Caecum digitulum

Caecum digitulum
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Order:	Mesogastropoda
Family:	Caecidae
Genus:	Caecum
Species:	C. digitulum
Binomial name
Caecum digitulum Hedley, 1904

Caecum digitulum is a species of minute marine gastropod molluscs in the Caecidae family, endemic to New Zealand including the Chatham Islands and The Snares.

They are found alive under stones in the upper tidal zone. Empty shells are dredged commonly to a depth of at least 90 m, and the coiled embryos seem to occur only in the dredgings.

The shells have discoidal nuclear whorls that are shed soon after the adult stage commences, which is in the form of a simple slightly curved tube, now sealed off above by a blunt rounded septum. The embryonic shell has 2½ smooth whorls, and the adult shell has the simple curved tube, pale brownish in life. The aperture is circular and so is the tight fitting operculum. The animal grazes upon filmy organic deposits, and moves about jerkily by advancing the foot and then dragging the shell in a series of short steps.

Height is up to 2.3 mm, and width 0.5 mm.

References

• Powell A W B, New Zealand Mollusca, William Collins Publishers Ltd, Auckland, New Zealand 1979 ISBN 0-00-216906-1