Hard Tube Worms

Scientific Name: Spirorbis sp.

Phylum: Annelida

Class: Polychaeta

Description: These worms are identified readily by the hard, limy tubes in which they reside. The Head has 1 tentacle modified to form a plug or operculum. Tiny tubes (~3mm) are flat or partly raised coils.

Distribution: Found in both inter-tidal and sub-tidal areas. Some attach to rock weeds and other bases, such as the back of crabs.

Locomotion: Movement within tube is usually accomplished by slow, peristaltic action of the body or by setal movements.

Feeding: Suspension feeders – feed on food particles suspended in the water. The radioles have a conveyor belt of cilia to carry entrapped particles suspended in the water. The ciliated groove of the conveyor belt mechanically sorts particles into 3 size classes. Small particles are carried to the mouth, medium particles are stored and large particles are rejected.

Gas Exchange: Branchial crown and internal circulatory system are used for transport of gases.

Reproduction: Asexual – worm divides in its tube, the lower part forming a new worm that bores out through the tube wall up take up residence next door. Sexual – the sexes are separate with eggs and sperm being released directly into water.