SOMATIC CHROMOSOMES IN VICIA 323 



SUMMARY. 



1. The resting nucleus contains a continuous reticulum in which the 

 various chromosomes can be distinguished as heavier bands, even in old 

 cells of the root (page 3io and fig. i). 



2. At prophase each reticulate band séparâtes from its neighbors. 

 The chromatic material condenses to an irregular région around the open 

 spaces and cavities, and forms a simple zigzag thread which becomes 

 straightened and equalized (pages 3ii-3i4 and fig. 2-9). 



3. The split occurs through axial vacuolization of the simple and 

 very thin thread and remains until the metaphase (pages 314-317 and 

 FIG. 10-24). 



4. Vicia affords no trustworthy évidence for the existence of morpho- 

 logical units or chromomeres (page 3i5). 



5. There is no continuous spirem either at prophase or telophase. 



6. The chromosomes are arranged on the spindle with their halves 

 always in superposition and separate into daughter chromosomes which 

 become massed at the pôles (pages 3oo-3o4 and fig. 22-33). 



7. The chromosomes gradually separate from each other at telophase, 

 remaining connected by anastomoses. They become irregularly alveolized 

 and iorm together a continuous resting reticulum (pages 3o4-3o8 and 

 fig. 34-39). 



8. The telophasic vacuolization has nothing whatever to do with the 

 longitudinal splitting of the chromosomes, which is a purely prophasic 

 phenomenon (compare with conclusions 2 and 3) (pages 3i8-32i). 



g. The results obtained in Vicia indicate the high probability of the 

 theory of the individuality of the chromosomes (page 322). 



To Professor Victor Grégoire the writer takes pleasure in expressing 

 his high appréciation of the advice so generously offered, and of the many 

 courtesies shown him during his sta}- in Louvain. 



Institiite Caruoy, Louvain. 



