1908] YAMANOUCHI—SPOROGENESIS IN NEPHRODIUM 27 



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1895. 

 48. , Ueber Reduktionstheilung, Spindelbildung, Centrosomen und 



•a» 



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49' , Ueber Reduktionstheilung. Sitzungsb. Konigl. Freuss. Akad. Wiss. 



18:587-614. figs. 4, 1904. 



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 1897. 



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ph. j~8, 1900. 



EXPLANATION OF PLATES I-IV 



AH figures were drawn with the aid of an Abbe camera lucida, using Zeiss 'S 

 apochromatic objective i .5"^^, N. A. 1.30, combined with compensating ocular 

 18, except figs, ija, i6a, lya, and ig, which were drawn with same combination 

 of objective and ocular under higher magnification obtained when the tube was 



extended to the farthest point. 



The plates are reduced one-half the original size, except plate i, which is 



reduced two -fifths. 



PLA TE I 



Vegetative mitosis in the sporogenous cell in the eight<eU stage 



Fig. I. The prophase; the spirem before segmentation into chromosomes; 

 a kinoplasmic cap with a few fibers at each pole; the membrane beginning to 



disappear at those points. 



Fig. 2. Spirem segmented into chromosomes; chromosomes long and 

 cur\-ed, split longitudinally, the two halves running closely in contact. 



Fig. 3. Chromosomes arranged parallel along the axis passing from^ pole 

 to pole, one end of chromosomes in which spindle fibers are attached lying in an 



equatorial plate. 



Fig. 4. The intermediate stage in passing from the previous condition to 

 the stage of an equatorial plate; the chromosomes much shortened, one end where 

 spindle fibers are attached being bent, while the end directed to the pole is strai^t. 



Fig. 5. Metaphase, showing an equatorial plate; chromosomes short and 



rod -shaped. 



Fig. 6. Late metaphase; the daughter chromosomes beginning to separate. 



Fig. 7. Anaphase; two sets of the daughter chromosomes on the way toward 

 pole; chromosomes ahnost straight, rod-shaped, sUghtly more elongated than 



metaphase. 



Fig. 8. Late anaphase; rod-shaped chromos<»nes paraUel at the pole.^ 



Fig. 9. Polar %-iew of stage given in previous figure, showing 12a chio- 



mosomes. 



