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:

31 μm 63 μm 94 μm; x 640

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).