PLATE II. 



FIG. 14. A more advanced stage in contraction, showing that adjacent threads 

 are anastomosing and fusing. X 1*400. Pinus Strobus. 



15. A still more advanced stage in the fusion of the threads. Practically 

 all evidence of the earlier longitudinal fission has now disappeared. 

 X 1*400. Pinus Strobus. 



16. The chromosomes becoming apparent. X 1*400. Pinus Strobus. 



17. Distinct chromosomes, in the one half or reduced number, arising 

 from the contracted and more or less anastomosed skein. X 1,400. 

 Pinus Strobus. 



18. a-c. Final stages in the formation of the chromosomes, showing the 

 separation of the segments from one another, and also the relation of 

 some of them to the nucleolus. X 1*400. Pinus Strobus. 



19. a-l. Various forms of chromosomes observed before the organization of 

 the spindle. Each chromosome consists of two of the longitudinal 

 split segments which were formed immediately subsequent to synapsis. 

 X 1 5400. Pinus Strobus. 



20. The chromatic segments completely differentiated. The remnant of a 

 nucleolus is still present, and the nuclear membrane is being resolved 

 into threads. X 1*400. Pinus Strobus. 



21. An early stage in spindle-formation, showing kinoplasmic threads 

 entering from all directions but as yet no poles, or centers of radiations, 

 have been established. Chromosomes are homogeneous in structure 

 and regular in outline. X 1*400. Pinus Strobus. 



22. The tripolar spindle. X 1,400. Pinus rigida. May 4, 1898. 



23. The spindle has become nearly bipolar. X 1*400. Pinus rigida. 



(158) 



