294 



BIOLOGY OF THE PROTOZOA 



brane of the parent eell (see p. 237). This method of sporula- 

 tion is frequent in rr()t()mastio:i(la and equally common amongst 

 these Polymastigida?. As the Diplozoa nia\' represent incompletely 

 divided individuals, so one group of the Polymastigida are gen- 

 erally interpreted as incompletely separated daughter cells which 

 have arisen through somatella formation. With Janicki, Doflein, 

 Koidzmni and others we include all such multiple forms under the 

 Tribe Polyzoa. Each of the one hundred or more nuclei of Steph- 

 anonymjjha (Fig. 141) is accompanied by similar kinetic elements, 

 flagella, blepharoplast and rhizoplast and, according to the hypoth- 



FiG. 141. — Stcphanonymphn sylvcstri; with many nuclei, kinetic groups, and 

 flagella. Rhizoplasts luiite to form the inner axial strand. (After Janicki.) 



esis, each complex represents a single ancestral organism (karyo- 

 mastigont). In Calomjmpha (Fig. 49, p. 98) the nuclei are less 

 numerous and some sets of kinetic elements are not accompanied 

 by nuclei, such aggregates are called akaryomastigonts by Janicki. 

 In all of these forms the rhizoplasts come together to form a distinct, 

 unified, and sometimes huge, axial strand (Fig. 141). This axial 

 strand is morphologically quite different from the axostA'le of mono- 

 zoic and polyzoic forms, where, according to Kofoid, this element 

 acts as an organ of locomotion, assisting a Trichomonas for example, 

 in making its way through the dense mucus of its environment. In 



