Pacific Lugworm

This ventral view of the head shows that it has no obvious external head appendages

This view, taken a few seconds after the one above, shows the large esophagus which is everted during feeding. The esophagus expands outward like the head of a mushroom.

The anterior third of the body, anterior to the gills, has relatively long segments and the notopodia and neuropodia are well separated. In this view the head is to the right and dorsal is up. The first gill-bearing segment is on the left. The capillarynotosetae-bearing notopodium can be seen near the top of the segment in the center, while the uncini-bearing neuropodium can be seen well below the notopodium next to the piece of debris.

The gills are notopodial (dorsal) and filled with hemoglobin-containing blood. The animal writhes and waves them gently, likely increasing water circulation over them. Note the long capillary setae on the notopodia (top) and the uncini on the neuropodia (lower).

The posterior segments have no setae, so that the back third of the body appears almost like a "tail". Note the last gill and setae-bearing segments at the right of the photo.

This is a view of the last segments and the pygidium (posteriormost segment)

This ventral view of the posteriormost gill-bearing segments shows that the neuropodia of these segments do not nearly meet at the midline.

The worm creates burrows with large mounds at the entrance such as this one. Often fecal castings can be seen on top of the mound.

Abarenicola pacifica, found on March Point, Padilla Bay, June 2009. View is of the dorsal and right sides. Anterior end is to the right. The red, bushy structures are gills filled with blood which has red hemoglobin. In closeup one can see that the gills are continually flexed and turned, providing water flow over them. (Photo by: Dave Cowles)