The literature is reviewed and observations are made on some recent records. Limapontia depressa is found not only on salt marshes but on the mud of estuaries, coves and inlets of the sea. Its habit of burrowing in wet mud suggests it was once an infaunal species. It feeds on Vaucheria and associated green algae. and on one occasion was observed feeding on Cladophora. The main anatomical differences between L. depressa and L. capitata are described. L. depressa may be regarded as a polytypic species with three subspecies: L. depressa depressa Alder and Hancock (black); L. d. olivaria nov. (dark olive to brown); and L. d. pellucida Kevan (chrome yellow and green).