Burrow morphology of the echiuran worm Maxmuelleria lankesteri (Echiura: Bonelliidae), and a brief review of burrow structure and related ecology of the Echiura <B>Burrow morphology of the echiuran worm Maxmuelleria lankesteri (Echiura: Bonelliidae), and a brief review of burrow structure and related ecology of the Echiura</B><P> </B><B>A. NICKELL(1), R. J. A. ATKINSON(2), D. J. HUGHES(1), A. D.<BR> ANSELL(1) and C. J. SMITH(3)</B><I><P> (1)Dunstaffnage Marine Laboratory, PO Box 3, Oban PA34 4AD, UK <BR> (2)University Marine Biological Station, Millport, Isle of Cumbrae KA28 OEG, UK<BR> (3)Institute of Marine Biology of Crete, PO Box 2214, 71003 Iraklion, Crete, Greece</I><P> (Accepted 10 May 1994)<P> The burrow morphology of the echiuran worm <I>Maxmuelleria lankesteri </I>(Herdman) was investigated <I>in situ </I>using a resin casting technique. Work was carried out in Lochs Sween and Creran on the west coast of Scotland in predominantly fine mud sediments. Burrow casts typically had only 1 opening, although there is evidence to suggest that a second opening may exist. In 58% of burrows, the<B> </B>opening, which was small and funnel-shaped, was<B> </B>associated with a surface mound reaching up to 20 cm in height. The tunnel below the burrow opening, the 'neck', was narrow and circular in transverse section with a smooth wall, possibly due to the action of the mucus-laden proboscis which emerges during feeding. The maximum burrow depth recorded was 80 cm and tunnel orientation became more horizontal with increasing depth. In some larger burrows, the tunnel began to orientate upwards towards its end. Below the neck, the tunnel was much wider but had a sub-circular transverse section. The burrows had distinct striations on the walls of lower tunnels, possibly caused by movements of the animal within. In some cases, a community<I> </I>of symbiotic organisms, had developed, including polychaetes and 2 species of bivalve, <I>Mysella bidentata </I>(Montagu) and <I>Saxicavella jeffresii </I>Winckworth. Evidence of burrow modification by the crustacean <I>Jayea nocturna </I>Nardo was noted and gobies, including <I>Gobius niger </I>Linnaeus, were also responsible for some alterations to the upper burrow around the opening. Evidence suggested that burrows were permanent structures which changed little in position.<B><P> KEYWORDS:</B> Burrow morphology, <I>Maxmuelleria, </I>Echiura, bioturbation, sea lochs, Scotland.<P> JOURNAL OF NATURAL HISTORY, 1994, <B>29., </B>871-885<P>