Region: cosmopolitan.
Habitat: sea; deep-water, exclusively benthic, near the bottom.
Genera: 28 families; 320 species.
ZoologyAplacophora are marine molluscs, very small, up to 5 cm, to 30 cm. They are shell-less, cylindrical and worm-like in form.
CladesSolenogastres (Neomeniomorpha): carnivores feeding on cnidarians or sometimes annelids.
Caudofoveata (Chaetodermomorpha): detritovores or feed on foraminiferans.
TaxonomyAplacophorans are traditionally considered ancestral to the other mollusca.