i 



AND THE EmBRVO-SAC IN BiGNONIA VENUSTA 105 



Fig. 20. Nucleus of the pollen mother-cell in synapsis. 

 Fig. 21. Longitudinal division of the spirem thread. 



Fig. 22. An early stage in the differentiation of tlie chiomosnmes in the nucleus of 

 the pollen mother-cell. 



Fig. 23. Nucleus with mature chromosomes. 



Fig. 24. Formation of the multipolar spindle. 



Fig. 25. The complete spindle of the pollen mother-cell showing scattered 

 chromosomes and nuclear hollow. 



Fig. 26. An enlarged view of a spindle in the same stage as in the preceding 

 figure. 



Fig. 27. A characteristic spindle in the anaphase of division. 



Fig. 28. A telophase of the first division in wliich the chromatic substance is 

 largely fused into a nucleolar-like body. 



Platk 354. 



Fig. 29. Compact second spindle of the pollen mother-cell. 



Fig. 30. An anaphase stage of the second division. 



Fig. 31. A telephase of division before the formation of a cell plate. 



Fig. 32. An early stage in the differentiation of the microsjiores. 



■m 



Fig. ;^;^. Various appearances of the chromatin content in the dispirem of the 

 second division, preceding the formation of a nucleolus. 



Fig. 34. Synapsis in the nucleus of the axial -row mother-cell. 



Fig. 35. A spirem stage in the nucleus of tlie axial-row ni(Hher-cell. 



Fig. 36. A nucleus showing longitudinal division of the spirem thread. 



Fig. 37. A nucleus with chn^mosomes well formed. 



Fig. 38. The first division in the macrosporic archcsporium. 



Fig. 39. A telephase stage in tlic same division. 



Fig. 40. Complete spindles of the second division hi the macrosporic archesporium, 



CORXKLL Univeusitv, Itjiaca, N. Y, 



