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:

50 μm 100 μm 150 μm; x 400

31 μm 63 μm 94 μm; x 640

A. inquieta (Biernacka, 1963): 170-200 μm long; with an elongate neck & rounded posterior; a row of four contractile vacuoles present laterally; two large spherical macronuclei (Carey, 1992).
A. lanceolatus Dragesco, 1965: lanceolate in form; 120 μm long; pointed both anteriorly and posteriorly; no elongate neck region; trichocysts in the buccal region and also scattered throughout cytoplasm; mucocysts present; a macronucleus consisting of two spherical bodies with a intercalated micronuleus; a single contractile vacuole with satellite vacuoles (Carey, 1992).