CHILOMASTIX MESNILI 



625 



(1914), are pear-shaped structures which vary in length from 7 to 10 microns 

 (Fig. 256, 11-14). In the majority of cysts one end is narrower than the 

 other, though occasionally the two ends are more alike. In the fresh 

 condition practically nothing of the internal structure can be made out, 



lf\ ttm 



Fig. ■2o7.^Ghllomastix aulastomi ( x 2,300). (After Belar, 1921.) 



1. Usual type of flagellate. 



2. Comtnencing division with two centrosomes on nuclear membrane. 



3. Spindle with centrosomes and chromosomes at equator of spindle; newflagellaare forming. 



4. Nuclear division nearly complete. 5. Commencing division of flagellate. 



though a few greenish refractile granules are sometimes seen. In iodine 

 solution the single round nucleus and the cytostomal cleft can be faintly 

 distinguished (Plate II., 24, p. 250). In stained specimens, however, 

 practically all the details which can be seen in the flagellates themselves 

 are visible. The nucleus is near the narrow end of the cyst, and near it can 

 I. 40 



