PLATE IX 



The Results of Crossing-over in Inversion Heterozygotes 



{cf. Text-Fig. 92) 



Figs. 1-3. — Chovihippus parallelus, ^. (D., 1936 d.) 



Fig. I. — Diplotene with chiasma between two relatively translocated 

 and inverted segments within the same bivalent (Text-Fig. 92 h). 



Fig. 2. — First anaphase, dicentric bridge and acentric fragment. 



Fig. 3. — Second anaphase, second division bridge in ISI chromosome. 



Fig. 4. — Beginning of first anaphase in Pceofiia, showing inversion 

 chiasma separating. [Cf. Dark, 1936.) 



Fig. 5. — Bridge and fragment in diploid Tiilipa, first anaphase 

 X 2000. (Upcott, unpublished.) 



Fig. 6. — Univalent and bivalent bridge formation in triploid Tulipa, 

 three acentric fragments. X 2000. (Upcott, unpublished.) 



Fig. 7. — Acentric ring chromatid produced by inversion crossing 

 over at first anaphase in Tulipa. X 1400. (Upcott, unpublished.) 



Figs. 8 and 9. — A ntric chromatid in pollen grain mitosis of 

 Podophyllum at two focuses. (D., 1936 b.) 



