peristomium. Guts of the deep-sea Chaetozone and Tharyx were filled with sediment.
Capitella (Fig. 13.7b), of the family Capitellidae, is a genus found at all depths. They
are also deposit-feeders with a simple, earthworm-like shape, but they have a sticky
eversible proboscis that probably has some role in selecting better food particles.
Flabelligella belongs to a group not well represented in shallow waters, and so not
well characterized; the deep-sea specimens had pelletized mud in the hindgut, and
they are likely also deposit-feeders. Fifth- and sixth-ranked species belonged to
families Paraonidae and Spionidae, which also feed on sediment, although probably
more selectively than the others. Thus, the dominant life mode is direct ingestion of
sediment, sometimes selecting or rejecting specific particle types.
Fig. 13.7 Worms from four families of polychaetous annelids very common in deep-
sea muds: (a) Cirratulidae, (b) Capitella of the Capitellidae, (c) Ampharetidae, and (d)
Glyceridae.
(^) (a & b after Day 1967; c & d after Fauchald & Jumars 1979.)