CHAPTER V 



PROTOZOA (CONTINUED) : FLAGELLATA 



III. Flagellata. 



Protozoa moving (and feeding in holozoic forms) by long flag ell a : 

 pseudopodia when developed usually transitory : nucleus single or if 

 multiple not biform : reproduction occurring in the active state and 

 usually by longitudinal fission, sometimes alternating with brood- 

 formation in the cyst or more redely in the active state : form 

 usually definite : a firm pellicle or distinct cell-wall often present. 

 The Flagellates thus defined correspond to Blitschli's group of 

 the Mastigophora. The lowest and simplest forms, often loosely 

 called "Monads," are only distinguishable from Sarcodina (especially 

 Proteomyxa) and Sporozoa by the above characters : their 

 artificial nature is obvious when we remember that many of the 

 Sarcodina have a flagellate stage, and that the sperms of bisexual 

 Sporozoa are flagellate (as are indeed those of all Metazoa except 

 Nematodes and most Crustacea). Even as thus limited the group 

 is of enormous extent, and passes into the Chytridieae and 

 Phycomycetes Zoosporeae on the one hand, and by its holophytic 

 colonial members into the Algae, on the other. 1 



Classification. 



A. Fission usually longitudinal (transverse only in a cyst), or if multiple, 

 radial and complete : pellicle absent, thin, or if armour-like, with not 

 more than two valves. 



I. Food taken in at any part of the body by pseudopodia 



1. Pantostomata 

 Multicilia Cienk. ; Mastigamoeba F. E. Sell. (Fig. 37, 4). 



1 The alleged micronucleus of certain forms appears to be merely a "blepharo- 

 plast " (see p. 19) ; even when of nuclear origin, as in Trypanosoma, it has no 

 function in reproduction like the micronucleus of Infusoria (see pp. 115, 120 f. ). 



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