i9o8] YAMANOUCHI— SPERMATOGENESIS AND OOGENESIS 175 



of sperm loosened into complex structure of chromatin clumps and fine strands; 

 three nucleoli in region of disintegrating sperm; upper side of figures toward neck. 



Figs. 54a, b. Two sections of egg nucleus containing a disintegrating sperm 

 in stage later than in last figures; neck toward the left. 



Fig. 55, Fusion nucleus after complete union of the two chromatin reticulums 

 of sperm and egg; ragged reticular structure homogeneous throughout; three 

 nucleoli present; upper side of figure toward neck. 



Fig. 56, Spirem of first segmentation di\ision of fusion nucleus shows a 

 continuous structure. 



Fig. 57. Anaphase of same mitosis; the two sets of chromosomes regularly 

 arranged at the poles. 



Fig. 58. Polar view of stage shown in Jig, 57; 128 chromosomes present. 



