CELL FORM AND SURFACE PATTERNS INCHROOMONASandCRYPTOMONASCELLS (CRYPTOPHYTA) AS REVEALED BY SCANNING ELECTRON MICROSCOPY1

Fifteen freshwater cryptomonad species were freeze‐dried and examined with the scanning electron microscope. Surveys of cell surfaces revealed four general cell types. Chroomonastype cells lack a furrow but possess a shallow vestibular depression where the flagella are inserted. The presence of a gullet could not be detected. Cryptomonasspp. displayed three morphological types, all lacking gullets. The first type ofCryptomonashas a simple, shallow furrow with ridges that apparently can close to form a raphe but an oval opening or stoma remains at the posterior end and an opening from the vestibulum is formed at the anterior end. The secondCryptomonastype consists of a complex furrow with furrow ridges and folds that extend almost two‐thirds of the cell length. A sloma is present in the central region of the closed furrow. The folds apparently can separate thereby exposing the underlying furrow. The third type ofCryptomonaspossesses a simple, non‐closing furrow. At the anterior end there is a vestibular ligule which extends from the dorsalleft side of the cell and covers the region of the vestibulum where the contractile vacuole discharges.