﻿1903] BEHAVIOR OF THE CHROMOSOMES 281 



Fig. 24. Three chromosomes at a little later stage seen obliquely from 

 the pole, X 1250. 



Fig. 25. Daughter nucleus showing hollow spirem ; the free ends indicate 

 where the spirem was cut by the microtome knife. 



Fig. 26. An entire pollen mother-cell showing the two multipolar spindles 

 of the daughter nuclei. X 1750. 



Fig, 27. A multipolar spindle of a daughter nucleus at a later stage than 

 the preceding, in which fewer poles are present; the chromosomes are being 

 arranged in the nuclear plate. 



Figs. 28, 29, Two mature spindles; although in fig. 2g the segments of 

 the chromosomes are not closely applied to each other, yet this is not a 

 later stage thany?^. 28, 



Figs. 30-39. Tradescantia virginica. 



Fig. 30, Mature spindle; the points of the crescent-shaped daughter 

 segments adhere to form ring-like chromosomes except in the one at the 

 right; two of the chromosomes are fastened together by the fusion of one 

 of the points of each crescent to one of the other; in the chromosome at the 

 right only one point of the segments adhere. X 1250. 



Fig. 31. The same stage as fig. jo; the daughter segments of the three 

 chromosomes on the left are united only at one end; they are short, thick 

 crescents with blunt ends, and when thus oriented they frequently reach 

 almost from pole to pole. X 1250, 



Fig. 32. The daughter segments have just separated ; at this stage the 

 second longitudinal fission is often not apparent. X 1250. 



Fig. 33. The anaphase ; at this stage it is evident that the daughter 



I chromosomes have split lengthwise. X 1250, 



I Fig. 34. The same stage ^sfig.jj; the chromosomes are seen from the 



'pole. X 1250. 



Fig. 35. Daughter nucleus seen from the pole: the granddaughter seg- 

 ments of the twelve chromosomes show a tendency to become separated ; 

 their surfaces present an eroded appearance, X 17S0. 



Fig. 36. Daughter nucleus in which the chromosomes are much reticu- 

 lated and the identity of the individuals cannot be definitely made out. 



X 1750. 



Fig. 37. Daughter nucleus in which all identity of the chromosomes Is 

 lost. X 1750. 



Fig. 38. The chromosomes are differentiated preparatory to the forma- 

 tion of the spindle. X 1750. 



Fig. 39. Mature spindle of second mitosis; the chromosomes are longer 

 and more regular than is usual. X 1750. 



Figs, 40-46. Embryo-sac of Lilitim Martagon. 



Fig. 40. Mature spindle of first karyokinesis in embryo-sac ; the chromo- 

 somes stand radially upon the spindle. X 1500. 



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