Lumbriculus is a genus of Annelid oligochaetes. Both the oligochaetes and the leeches, having no hard parts, do not fossilise well. Further growth sees an increase in the volume of amphipods, small fish and oligochaetes taken. Setae in oligochaetes (a group including earthworms) are largely composed of chitin. Oligochaetes evolved from polychaetes and the leeches branched off from the oligochaetes. Meiofaunal composition at the Marina Beach chiefly includes turbellarians, nematodes, polychaetes, oligochaetes, and harpacticoids. Almost 1000 species of oligochaetes live in Europe. Microsporidia are known to produce xenomas in oligochaetes, insects, crustaceans and fish. This lifestyle has evolved independently in sediment-dwelling ciliates, oligochaetes, nematodes, flatworms and bivalves. Freshwater hoplonemerteans are known to feed on oligochaetes, unicellular organisms, insect larvae, and other crustaceans. How prominent morphallactic regeneration is in oligochaetes is currently not well understood. Some small tube-dwelling oligochaetes transmit myxosporean parasites that cause whirling disease in fish. Only a few aquatic oligochaetes have eyes, and even then they are only simply ocelli. Myxospores are infective to oligochaetes, and are found among the remains of digested fish cartilage. Terrestrial oligochaetes are commonly known as earthworms and burrow into the soil.