﻿3 1 8 BOTANICAL GAZE TTE [may 



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Leipzig. 1890. 

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Oxford. 1900. 

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EXPLANATION OF PLATE XV, 



The figures were drawn with the aid of Abbe's camera lucida, Zeiss 

 homogeneous immersion, objective j^sj^pert. 1.25, compensating ocular no. 8. 



Fig. I. A portion of a pollen mother-cell of Passiflora coerulea during 

 nuclear division ; the figure shows the chromosomes of one daughter nucleus 

 at the poles ; the connective fibers are still attached to the chromosomes but 

 otherwise the latter lie freely in the cytoplasm. 



Fig. 2. A later stage of the same ; the chromosomes have fused together 

 and the daughter nucleus is represented as a large single irregularly shaped 

 mass of chromatin. 



Fig. 3. Shows the presence of small lacunae within the chromatin mass 

 of the daughter nucleus ; these lacunae are the first indications of the accu- 

 mulation of the nuclear sap or karyolymph. 



Fig. 4, Shows an increase in the amount of karyolymph; the smaller 

 lacunae have united, forming one central cavity and the chromatin has the 

 appearance of a sphere with the karvolymph in the center; in section the 

 daughter nucleus has the appearance of a ring of chromatin surrounding a 

 central cavity of karyolymph. 



Fig. 5. Shows a somewhat later stage than fig. 4; the karyolymph has 

 increased in quantity and the chromatin has undergone still further modifica- 

 tions in its shape ; up to this stage no trace of a nuclear membrane could be 



detected ; the chromatin lies freely in the cytoplasm. 



Fig. 6. This shows a stage in the daughter nucleus where the karyolymph 



has increased to such an extent and the chromatin has become so divided 

 that the latter is no longer completely surrounded by cytoplasm ; as a result 

 the cytoplasm is for the first time exposed to the karyolymph; at the region 



