FLAGELLATA  , the name given to the

Protozoa whose dominant phase is a " flagellula," or cell-body provided with one, few or rarely many long actively vibratile, cytoplasmic processes . Nutrition is variable: (r) " Holozoic "; food taken in by ingestion, by amoeboid action either unspecialized or at one or more well-defined oral spots, or through an aperture (mouth); (2) " Saprophytic " ; food taken in in solution through the general surface of the body; (3) " Holophytic "; food-material formed in the coloured plasm by fixation of carbon from the medium, with liberation of oxygen, in presence of light, as in green plants . Fission in the " active " state occurs and is usually longitudinal . Multiple fission rarely occurs save in a sporocyst, and produces microzoospores, which in some cases may conjugate with others as isogametes or with larger forms . (megagametes) . " Hypnocysts " to tide over unfavourable conditions are not infrequent, but have no necessary relation to reproduction . Many have a firm pellicle which may form a hard shell: again a distinct cell-wall of chitin or cellulose may be formed: finally, an open cup, " theca," of firm or gelatinous material may be present, with or without a stalk: such a cup and stalk are often found in colonial species, and are subject to much the same conditions as in Infusoria . The nucleus is simple in most cases; but in Haemoflagellates it is connected with a second nucleus, which again is in immediate relation with the motile apparatus; the former is termed the " trophonucleus," the latter the " kineto-nucleus." As reserves the protoplasm may contain oil, starch, paramylum, leucosin (a substance soluble in water, and of doubtful composition), proteid granules .