Pomatoceros triqueter

Keelworm (Pomatoceros triqueter)

The tube in which the worm hides at low tide is white and smooth, irregularly curved, hard and calcareous with a single prominent ridge along its back. It looks triangular in cross-section. The worm itself is small with varied colouration,  and has a crown of feeding tentacles. Similar to Pomatoceros lamarcki which has two ridges each side as well as a centre ridge. Tube width 3 to 5mm. Worm length up to 25mm.

Found encrusting and scarring rocks and shells on the middle to lower shore. Discovered on most types of coastline. Common and widespread.

Photograph taken August 2015, Meadfoot Beach, Torquay, Devon. Camera Nikon D3200, with Sigma 105mm macro lens. © Pete Hillman 2015.

Master Builders

Sand Mason Worm (Lanice conchilega)

The Sand Mason Worm fashions a tube made from cemented sand grains and tiny fragments of seashell. It has a frayed edge around the mouth, and can be seen at low tide protruding from the sandy beach.

The worm itself is pink, yellowish or greenish with white tentacles and red gills. It can have up to 300 segments, and grows up to 30cm long.

It may be found solitary or in great masses, and as many as several thousand can be within one square metre. Found on exposed and sheltered beaches where it feeds on organic food particles beneath the water via its tentacles which protrude from the top of its protective tube. Common and widespread.

Photograph taken August 2011, Saundersfoot, Wales.