66 PROTOZOOLOGY 



In the Myxosporidia and Actinomyxidia, there appear, during 

 the development of s})ore, 1-4 special cells which develop into 1-4 

 polar capsules, each, when fully formed, enclosing a more or less 

 long spirally coiled hollow thread, the polar filament (Fig. 221). 

 The polar filament is considered as a temporary anchoring or- 

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

 entrance into the alimentary canal of a suitable host. The nema- 

 tocysts (Fig. 104, b) of certain dinoflagellates belonging to Nema- 

 toidium and Polykrikos, are almost identical in structure with 

 those found in the coelenterates. They are distributed through 

 the cytoplasm, 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 nemato- 

 cysts in these protozoans is not understood. 



The parabasal apparatus 



In the cytosome of many parasitic flagellates, there is frequent- 

 ly present a conspicuous structure known as the parabasal ap- 

 paratus (Janicki), consisting of the parabasal body and the 

 thread (Cleveland), which latter may be absent in some cases. 

 This structure varies greatly among different genera and species 

 in appearance, structure and position within the body. It is 

 usually connected with the blepharoplast and located very close 

 to the nucleus, though not directly connected with it. It may be 

 single, double, or multiple, and may be pyriform, straight or 

 curved rod-like, bandform, spirally coiled or collar-like (Fig. 23). 

 Kofoid and Swezy considered that the parabasal body is derived 

 from the nuclear chromatin, varies in size according to the meta- 

 bolic demands of the organism, and is a "kinetic reservoir." On 

 the other hand, Duboscq and Grasse maintain that this body is 

 the Golgi apparatus, since 1) acetic acid destroys both the para- 

 basal body and the Golgi apparatus; 2) both are demonstrable 

 with the same technique; 3) the parabasal body is made up of 

 chromophile and chromophobe parts as is the Golgi apparatus; 

 and 4) there is a strong evidence that the parabasal body is secre- 

 tory in function. According to Kirby, who has made an extensive 

 study of this organella, the parabasal body could be stained with 

 Delafield's haematoxylin or Mallory's triple stain after fixation 

 with acetic acid-containing fixatives and the body does not show 



