66 



PROTOZOOLOGY 



The polar filament is considered as a temporary anchoring organella 

 of the spore at the time of its germination after it gained entrance 

 into the alimentary canal of a suitable host. In the Microsporidia, 

 the filament may or may not be enclosed within a capsule. The ne- 

 matocysts (Fig. 110, h) of certain dinoflagellates belonging to Nema- 

 toidium and Polykrikos, are almost identical in structure with those 



Fig. 23. Parabasal apparatus in: a, Lojihomonas blattarum (Kudo); 

 b, Metadevescovina debilis; c, Devescovina sp. (KirbjO- af, axostylar fila- 

 ments; bl, blepharoplasts; f, food particles; fl, flagella;n, nucleus; pa, para- 

 basal apparatus. 



found in the coelenterates. They are distributed through the cyto- 

 plasm, and various developmental stages were noticed by Chatton, 

 and Kofoid and Swezy, which indicates that they are characteristic 

 structures of these dinoflagellates and not foreign in origin as had 

 been held by some. The function of the nematocysts in these proto- 

 zoans is not understood. 



The parabasal apparatus 



In the cytosome of many parasitic flagellates, there is frequently 

 present a conspicuous structure known as the parabasal apparatus 

 (Janicki), consisting of the parabasal body and often thread (Cleve- 

 land), which latter may be absent in some cases. This structure 



