Caecidae is a taxonomic family of minute sea snails or micromolluscs, marine gastropod molluscs in the order Littorinimorpha.

Habitat

These minute tubular shells can be found living in marine sediment, or among algae or sponges, in warm and temperate seas.

Shell description

The shells in this family are unusual in that the adult shell is a curving tube. In the subfamily Caecinae the protoconch is lost, and the tube is sealed with a permanent calcareous plug at one end. In the subfamilies Ctiloceratinae and Strebloceratinae the protoconch is retained. At the other end, the tube is sealed by a circular operculum. The spiral part is almost always lost when outgrowing the juvenile stage. The color of the shell is white to pale yellow.

Taxonomy

This family contains three subfamilies:

Genera