Fragments of a large tube built of pieces of coarse gravel and shell, evidently the work of some Polychæte, have been constantly dredged for many years on the grounds in the neighbourhood of the Mewstone and Stoke Point, to the eastward of Plymouth Sound. Not until June 4th, 1903, was the worm first discovered to whose skill as a mason these tubes are due. On that day the Laboratory fisherman captured and drew attention to a tube which was occupied by a living worm. The specimen, along with a number of fragments of empty tube, was obtained on a patch of coarse gravel off Stoke Point.