Bristle Worm

How to Distinguish from Similar Species: The membrane which connects the base of the radioles, forming them into a funnel, is a distinctive feature of this species when combined with abdominal uncini which form bands nearly around the body. A second, related slime-tube worm, M. asthetica, has also been reported to be in the region. It has only 1-4 thoracic setigers and a single apical tooth on the abdominal uncini, and it often attaches to ropes.

In rock crevices or on floats. Sometimes buried in soft mud.

Geographical Range: Pacific coast of North America from the Bering Sea to California and in the Atlantic ocean.

Depth Range: Intertidal to 425 m.

Like all members of Family Sabellidae, this species has a plume of pinnate, featherlike radioles on its head region and lives in a flexible, leather or parchment-like tube it has secreted. Like serpulids, the head has a series of pinnate radioles with which the animal suspension feeds. Unlike serpulids, the radioles are not spiraled but form a series of semicircles around the head region. In Myxicola infundibulum none of the radioles have conspicuous ocelli curled around them near their tips. Unusually, the proximal part of the radioles are connected to one another by a membrane so that they form a funnel. The thorax is longer than in most local sabellids--8 setigers. The first 5 or 6 thoracic neuropodia have long-handled uncini and no pickaxe-shaped setae. The abdominal uncini occur in rows that extend much of the way around the segments and they have several apical teeth. They secrete gelatinous tubes of mucus. The color of the plume of radioles is yellow to greenish, brown, or brownish-purple. Worm is up to 9 cm long.

Biology/Natural History: These worms are often found as an aggregation in which the individual members secrete so much slime that they make a boulder-shaped colony. They withdraw rapidly into the clear mucus tubes when disturbed or when a shadow passes over. Silt and small debris may cover the mucus, masking its transparency. At other times, they build their mucus tubes wedged between other species of worms, mussels, or tunicates. This species can withdraw into its mucus tube very rapidly, by use of a giant ventral axon. That axon extends throughout the length of the body and has been the subject of much research on neural activity. It comprises 27% of the animal's entire nervous system. Nerve impulses travel at 6-20 m/s along the axon. The quick withdrawal into the tube not only shelters the worm from predators but forcefully ejects wastes from the tube. Unlike in some other sabellids, the crown of radioles is not autotomized to escape predators, and if the animal loses its radioles it will likely die. The name 'Myxicola' means 'living in slime' and 'infundibulum' refers to the funnel shape formed by the radioles.

Myxicola infundibulum is a species of polychaete worm from the family Sabellidae. The body consists of a head, a cylindrical, segmented body and a tail piece. The head consists of a Prostomium (part of the mouth) and a peristomium (area around the mouth) and carries paired appendages (palps, antennae and cirri).

Maine to New York; entire Pacific Coast

circalittoral of the Gulf and estuary