274 



THE PROTOZOA 



of flagellar insertion, characteristic of this order ; but it is simplest to regard 

 it merely as a secondary complication of the second type, and one which is 

 not universal in this order, since in Copromonas subtilis the blepharoplast 

 remains undivided, so that this species shows a flagellar attachment strictly 

 of the second type. In Euglena, according to Wager (213), the flagellum 

 passes through the oesophagus and becomes attached to the wall of the 

 reservoir-vacuole by a bifurcate base. On one of the branches is a distinct 

 thickening in close contact with the stigma (p. 205). The thickening is prob- 

 ably the blepharoplast, and the two branches represent the rhizoplast. 



The sexual processes of the Euglenoidina are but little known, and Copro- 

 monas is the only genus in which the complete life-cycle has been worked out ; 

 in this species it is of a simple type (p. 264, Fig. 111). 



The order comprises three families. The first, Euglenidce, contains forms 

 provided with cliromatophores, holophytic, saprophytic, and parasitic 

 (Haswell) in habit. Examples: Euglena (Fig. 4), Pliacus (Fig. 118). The 

 second family, Astasiidce, contains the genus Astasia (Fig. 15), colourless 



and saprophytic or parasitic. The third family, Per- 

 anemidce, contains numerous genera without chro- 

 matophores. holozoic or saprophytic. Examples : 

 Peranema, Copromonas (Fig. 111). Tho subfamilies 

 Heteronemince and Anisonemince are heteromastigote. 

 Example : Anisonema (Fig. 25). 



ORDER V. : CHROMOMONADINA. Small forms, with- 

 out oesophagus or vacuole-system, with delicate cuticle 

 and one or two flagella ; their characteristic feature is 

 the possession, usually, of one or two conspicuous 

 cliromatophores, green, yellow, or brownish, in colour. 

 The nutrition, for the most part holophytic, may 

 be also holozoic or saprophytic. Divided into two 

 suborders. 



Suborder 1 : Chrysomonadina. With one or two 

 flagella and one or two yellowish-brown chroma- 

 tophores ; body often amoeboid or metabolic ; colony- 

 formation frequent ; nutrition holozoic and holophytic. 

 Three families. Examples : Chrysamosba, Chromulina, 

 Dinobryon, etc. According to Scherfl'el, Chrysamceba 

 is the amoeboid, non-flagellated phase of Chromulina ; 

 compare also Lauterborn (345'5). To this suborder 

 must be referred also the Coccolithophoridce. marine 

 flagellates which secrete the calcareous shells known as 

 coccoliths (vide Lohmann). 

 Suborder 2 : Cryptomonadina. Small forms with one or two flagella, colour- 

 less, or with chromatophores ranging in colour from yellowish-brown to olive- 

 green or blue-green. Holophytic or saprophytic, not holozoic. Examples : 

 Chilomonas, colourless ; Cryptomonas, some species of which are symbiotic in 

 Sarcodina (p. 15). Doflein refers the Silicoflagellata to this order (p. 255). 



ORDER VI. : PHYTOMONADINA SETT PHYTOFLAGELLATA. Completely and 

 exclusively holophytic, with cellulose envelope and without mouth-aperture. 



This order comprises the most plant-like flagellates, to all intents and 

 purposes unicellular algae which retain throughout life their flagellar apparatus 

 and their motility. The individual is generally small, and the body is, except 

 in one family, of definite form and enveloped in a rigid cellulose envelope 

 which may stand off from the body, and is perforated by pores through which 

 the flagella pass out to the exterior. The flagella are usually two in number, 

 sometimes four, of equal size. The cytoplasm generally contains a large 

 green chromatophore and a red stigma. The flagellar insertion, according 

 to Hartmann and Chagas, is of the second type, as in Protomonadina. The 

 reproduction may take the form of multiple fission within the body-envelope 

 to form numerous swarm-spores, which when set free may be gametes or 

 agametes. Colony-formation is frequent in this order (p. 257). 



FIG. 118. Phacus 

 triqueter. ces., (Eso- 

 phagus ; c.v., con- 

 tractile vacuole ; st., 

 stigma ; A T ., nucleus. 

 After Stein. 



