Phylum Rotifera (wheel animals)
Approximate Number of Species: 1,800
Largest: Asplanchna sieboldii at a length of 0.098 inches (2.5 mm)
Smallest: Colurella tesselata at a length of 0.002 inches (0.055 mm)
References:
Higgins RP & Thiel H eds (1988) Introduction to the study of meiofauna (Smithsonian Institute Press, Washington, D.C.).
Brusca RC & Brusca GJ (2003) Invertebrates (Sinauer Associates, Inc., Publishers, Sunderland, MA) 2nd Ed.
Koste W (1978) Die Raedertiere Mitteleuropas (Borntraeger, Stuggart).