MATURATION OF GAMETES 



141 



the tetrads become arranged on the metaphase plate of the first maturation 

 division. (See figs. 69, first maturation division; 72F, 119A, B.) This division 

 is described on pp. 132 and 133. 



d. Peculiarities of Nuclear Behavior in the Oocyte During Meiosis; 

 the Germinal Vesicle 



Although the movements of the chromosomes during meiosis in the devel- 

 oping male and female gamete appear to follow the same general behavior 



ACROSOME 



Q NUCLEUS 

 I TOCHONDRIA 



Fig. 75 



TA I L 



Fig. 76 



Fig. 75. Non-fiagellate sperm. (A-C) Ameboid sperm of Polyphemus. (After Zach- 

 arias.) (D) Lobster, Homarus. (After Herrick.) (E) Decapod Crustacea, Galathea 

 (Anomura). (After Koltzoff.)' (F) Nematode woim, Ascaris. 



Fig. 76. Conjugate sperm of grasshopper associated temporarily to form the "sperm boat." 



pattern (fig. 67), some differences do occur. For example, in the female when 

 the diplotene stage is reached, the repulsion of the tetrad threads is greater 

 (figs. 67, i and $ ; 72). Furthermore, the chromatids elongate and become 

 very attenuate although they appear to retain their contacts or chiasmata 

 (fig. 72). Side loops and extensions from the chromatids also may occur, 

 especially in those vertebrates with large-yolked eggs (e.g., amphibia, fishes, 

 etc.). (See figs. 71H, 72B-D.) When these lateral extensions are present, the 

 chromosomes appear diffuse and fuzzy, taking on the characteristics which 



