Eight phyla, Gastrotricha, Kinorhyncha, Priapulida, Gnathostomulida, Loricifera, Archiannelida, Rotifera and Tardigrada, are grouped together as the meiofauna. Most of these minute, often microscopic, animals live between grains of sand and mud in fresh water, on beaches and on the seafloor. The rotifers and tardigrades live in a wide variety of aquatic habitats including sand, mud and damp moss. Except for tardigrades which feed by sucking plant juices, most meiofauna feed on even smaller organisms like bacteria, diatoms and protozoa and are important as the base of many food chains.
Only Priapulus from Lochmaddy, North Uist, which is exceptionally large and easy to see, is shown here. Its proboscis is armed with many teeth and used for capturing prey and burrowing.