32 



GENERAL ORGANIZATION OF THE PROTOZOA 



axial filaments, and with their formation the young organism for the 

 first time assumes the appearance of a heliozoon (Fig. 11, F, G). 



These structures of the protozoa certainly justify, if any do, the use 

 of the term kinoplasm. Not only are they connected with the activity 

 of the cell in division, but they are also closely identified with the 

 motile organization of the cell. In heliozoa, as already pointed out, 

 they are the centres for the formation of the axial rays of the pseudo- 

 podia, which vary in motile power from practically quiescent append- 

 ages in forms like Actinophrys sol, through a slight elasticity in forms 

 like acanthocystis to vigorously vibratile appendages in artodiscus, 

 which cause the minute organism to dance about the field on the tips 



Fig. 12 



Dimorpha mutans. (After Schoutetlan.) Two flagella and radiating axial filaments 

 centring in the extranuclear division centre. 



of its pseudopodia. The similarity between these axial filaments and 

 flagella of the flagellated organisms is well shown in the case of Dimor- 

 pha mutans, in which the majority of the axial filaments are similar 

 to those of other heliozoa, but two of them remain uncovered by stream- 

 ing protoplasm and whip about in the surrounding water like the 

 vibratile lashes of the flagellates. One of these flagella, according to 

 Schoutedan ('07) serves to anchor the animal, while the other provides 

 a food current (Fig. 12). In such cases the close connection of these 

 axiopodia with flagella is clearly shown and may well help to point 

 out the course of evolution of heliozoa and flagellates, perhaps the 

 former from the latter. 



The actual participation of such division centres in the formation 



