Genus: Small amoeba with rapidly changing form; sometimes spatulate or flabellate; hyaline zone usually with smoothly irregular edge; sometimes deeply divided; one known species ? (Page, 1976). Species:

50 μm 100 μm 150 μm; x 400

R. ithacus: 5-17 μm, exceptionally 25 μm (Page, 1976). Locomotive 5-15 μm long, rarely to 25 μm; pseudopods clear, eruptive; uroid none (Illustrated Guide, 1985).