REPRODUCTION 



105 



selves into two compact daughter nuclei. A detailed study of micro- 

 nuclear division (Fig. 67) of Urostyla grandis was made by Raabe 

 (1946). The micronucleus is a compact body in the interphase (a), 



Fig. 67. Micronuclear division of Urostyla grandis, X2100 (H. Raabe). 

 a, resting stage; b-j, prophase (b-e, stages in the formation of spireme; 

 f, g, spireme ribbon; h, i, twelve segments of ribbon arranged in the direc- 

 tion of the elongating nuclear axis; j, a polar view of the same); k, 1, 

 metaphase, condensation of the segments; m-o, anaphase; p, late ana- 

 phase; q, a daughter nucleus in telophase; r-t, reconstruction stages; u, a 

 resting daughter nucleus. 



