3§4 
Digby . — The Cytology of Primula kewensis 
6. In P. verticillata there is a typical second contraction. 
In P. kewensis (type) the spireme segments tend to amalgamate in 
parts, but they never form a definite second contraction. 
7. In P. kewensis (seedling form) two of the bivalent chromosomes 
join together in the heterotype prophase of the pollen mother-nuclei, form- 
ing a large quadrivalent chromosome. This union is maintained until its 
univalent portions separate on the spindle. 
In the homotype division all the chromosomes behave normally. 
There is also no connexion between two of the chromosomes in the first 
meiotic division of the embryo-sac mother-cell. 
8. P. kewensis (seedling form) has a most typical diakinesis. The 
chromosomes are extremely contracted and are widely separated from one 
another, but are connected together by fine tightly stretched threads. The 
ordinary bivalent chromosomes resemble dyads, the quadrivalent chromo- 
some a tetrad. 
9. Protrusions of chromatin from a nucleus into the adjacent cell are 
sometimes found in the ‘ open spireme ’ stage of P. kewensis (type). 
In conclusion I wish to express my most grateful thanks to Professor 
J. Bretland Farmer, F.R.S., for the valuable help and advice that he has 
given me throughout the course of this work. 
Royal College of Science, 
London. 
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