Plate V 



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A F, prophases of heterotype division of spermatocytes of Guinea-pig, after 

 MOORE and WALKER. A, spireme (leptonetna), B, synizesis (contraction 

 phase), C, zygonema, D, pachynema, E, resolution of contraction phase. 

 F, appearance of definite double chromosomes. 



G, H, /, heterotype division in spermatocytes of the Grasshopper Stenobothrus, 

 after DAVIS. G, /f, Metaphase, 7, Anaphase. 



