body elongate-ovate, broader anteriorly than posteriorly
length 14–28 µm
two flagella equal in length, slightly shorter than cell
anterior cytopharynx surrounded by refractile ejectisomes
nucleus is located posteriorly to the cytopharynx
small extrusomes under cell membrane
contractile vacuole is located anteriorly
often two refractile Maupas’ bodies
rotates while swimming, can also swim backwards, occasionally jumps backwards
frequently cell is filled with starch grains
cell colorless, without chloroplasts
Cryptomonas paramecium (until 2003 Chilomonas paramecium) is a heterotrophic cryptomonad that has all the characteristics of the genus Cryptomonas except for the chloroplasts. The colorless flagellate feeds on dissolved nutrients (saprophytically) and on bacteria. It can also be grown in pure nutrient solutions. The species is common in all my localities where there are decaying plant masses. Mass development sometimes occurs in old samples.
Fig. 1:Cryptomonas paramecium. L = 21 – 27 µm. A sample with a mass development. Obj. 100 X.
Fig. 2 a-c:Cryptomonas paramecium. L = 26 µm. A freely swimming specimen in frontal view (a, b) and lateral view (c). CV = contractile vacuole, EJ = cytopharynx with ejectisomes, MB = Maupas’ bodies, SG = starch grains. Obj. 100 X.