Ventral view

Description :

Gastronauta membranaceus (Engelmann in Bütschli,1889), a hypostome ciliate, distinguished by its long transversely oriented cytostome. The cytostome lacks trichites. The body is ovoid in outline and strongly dorsoventrally flattened. Ciliature is restricted to the ventral surface except for two short dorsal kineties anteriorly. A few somatic kineties run uninterrupted to the right of the cytostome arching around the anterior of the cell. Several right somatic kineties are interrupted by the cytostome. The left somatic kineties terminate at the cytostome. A single kinety runs around the circumference of the cytostome. An unciliated bare are overlies the region of the macronucleus posterior to the cytostome. The macronucleus is oblong and heteromerous (i.e. containing areas with markedly differing RNA and DNA contents resulting in irregular staining and optical characteristics). The single micronucleus is quite prominent. Two contractile vacuoles are present, one in the anterior half and one posteriorly. Gastronauta feeds mainly on diatoms. From a freshwater pond near Boise, Idaho. DIC. This image was taken by William Bourland. He now uses a Zeiss Axioskop 2 with a Spot Insight CCD camera (Diagnostic Instruments).