1 66 
Digby . — On the Archesporial and 
in both instances would be considered to be splitting asunder instead of 
approaching each other. 
7. In the same sporangium nuclei in widely separated stages may occur 
(PI. XII, Fig. 101), testifying to the rapidity with which the nuclear phases 
are passed through. Sporangia have been found in which some of the spore 
mother-nuclei are in pre-second contraction, whilst others are in diakinesis 
(Fig. 101) ; again, some of the nuclei may be in second contraction, while 
others are in metaphase. 
8. Several cases of synangia have been found, one in archesporial 
division (Fig. 102) ; the others have their spore mother-cells in the first 
meiotic division (Figs. 103, 104, 105, and 106). The nuclei of one side of 
the synangium may be in a considerably more advanced stage than those of 
the other (Figs. 105 and 10 6). 
Chief Results of the Foregoing Investigation. 
1. It is shown that telophasic events have an important bearing on the 
interpretation of the succeeding prophase. 
2. That the sequence of events in prophase can only be interpreted in 
the light of the preceding telophase. 
3. The above-mentioned facts have been found to be of fundamental 
importance in elucidating the early stages of the heterotype division. 
4. In the heterotype division the prophasic stages, ordinarily included 
under ‘ synapsis do not consist in the lateral conjunction of two entire 
somatic chromosomes, but in the lateral reassociation of the threads in 
pairs which together make a single entire somatic chromosome. 
5. Conjunction in pairs of entire somatic chromosomes occurs in the 
stages leading up to, and is finally consummated during, second contraction. 
In conclusion I wish to express my great indebtedness to Professor 
Bretland Farmer, F.R.S., for his most valuable advice and criticism, and also 
for his kindness in affording me facilities which have rendered the comple- 
tion of this investigation possible. 
The Botanical Laboratory, 
Imperial College of Science and Technology. 
Bibliography. 
1. Bower, F. O. (1900) : II. Studies in the Morphology of Spore-producing .Members. No. IV. 
The Leptosporangiate Ferns. Phil. Trans. Roy. Soc., B., cxcii, pp. 29-138, 
2. Derschau, M. von (1909) : Beitrage zur pflanzlichen Mitose : Centren, Blepharoplasttn. 
Pringsh. Jahr. wiss. Bot., Leipzig, xlvi, Heft I, pp. 103-18. 
3. Digby, L. (1910) : The Somatic, Premeiotic, and Meiotic Nuclear Divisions of Galtonia 
candicans. Ann. of Bot., xxiv, No. 96, Oct., pp. 727-57. 
(1912): The Cytology of Primula kewensis and of other related Primula Hybrids. 
Ann. of Bot., xxvi, No. 102, April, pp. 358-88. 
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