Genus: Flask-shaped; ciliation uniform and complete; slit-like cytostome not reaching the middle of body, without trichocyst-borders; two or more macronuclei (Kudo, 1966). Many contractile vacuoles along both dorsal and ventral edges (Carey, 1992). Species:

100 μm 200 μm 300 μm; x 200 : 50 μm 100 μm 150 μm; x 400

A. lanceolatus (Dragesco, 1965): 120 μm long; pointed both anteriorly and posteriorly; no elongate neck region; trichocysts in the buccal region and scattered throughout the cytoplasm; two macronuclei with an intercalated micronuleus; a single contractile vacuole terminal with satellite vacuoles (Carey, 1992).