REPRODUCTION 



135 



blepharoplast ring; the centriole divides and the desmose which 

 grows, now stains very deeply, the centrioles becoming more con- 

 spicuous in the anaphase when new flagella develop from them. 

 Chromatin granules become larger and form a spireme, from which 

 6-8 chromosomes are produced. Two groups of chromosomes move 

 toward the opposite poles, and when the division is completed, each 

 centriole becomes the center of formation of all motor organellae. 



Fig. 61. Mitosis in Spirotrichonympha polygyra (Cleveland), a, resting 

 nucleus with 4 chromosomes; b, c, prophase; d, chromosomes moving 

 apart; e, elongation of nucleus; f, telophase; g, a daughter nucleus in 

 which the chromosomes are splitting, a-e, X3800; f, g, X2400. 



In some forms, such as Noctiluca (Calkins), Actinophrys(Bglaf), 

 etc., there may appear at each pole, a structureless mass of cyto- 

 plasm (centrosphere), but in a very large number of species there 

 appear no special structures at poles and the spindle fibers become 

 stretched seemingly between the two extremities of the elongating 



