in Lilium Mavtagon : II. Spermatogenesis. 221 
POSTSCRIPT. 
The twisted V-shape is characteristic of the diaster-segment in both 
heterotype divisions, and may easily give rise to misconception. Thus 
Professor E. B. Wilson (The Cell in Development and Inheritance, 
p. 197) has pointed out that one of my figures, representing a pair of 
such chromosomes en face , would suggest that each daughter-chromo- 
some is already divided transversely. Such an appearance is in fact 
not uncommon, but in studying the actual preparation it can as 
a rule be quite clearly made out that the daughter-chromosomes 
are neither divided nor even constricted. They are usually con- 
torted, however, by a sort of double twist near the middle of each. 
This may be more easily followed in the chromosomes of the first 
embryo-sac karyokinesis (I, Figs. 23 and 24. Compare especially 
the chromosomes 1-4 in Fig. 24 -with those of Fig. 23 and with 
Figs. 13 and 14 of this part). It will be seen later on that this 
twisted V-shape reappears in most of the chromosomes belonging to 
the second karyokinesis in the pollen-mother-cell (Figs. 18, 19). No 
transverse division has therefore taken place since the first karyokinesis, 
nor is any indicated in the chromosomes of the daughter-nuclei, which 
shortly afterwards divide by longitudinal fission (p. 207). 
Quarry Hill, Reigate, 
April 27, 1897. 
EXPLANATION OF FIGURES IN PLATES 
X AND XI. 
Illustrating Miss E. Sargant’s paper on the Nuclei of Lilium Martagon. 
The figures marked x 585 were drawn from Zeiss’ apochromatic hom. im. 
objective, 2 m.m. focal length, N. A. 1 -30, with eye-piece 4 ; and those marked 
x 290 and X300 with the same objective, eye-piece 2. The figures marked 
X 1000 were drawn under Zeiss’ apochromatic hom. im. objective, 1-5 m.m. focal 
length, eye-piece 6. Figs. 30 a and 31 were drawn under Zeiss’ apochromatic 
objective, 16 m.m. focal length, with eye-pieces 6 and 4 respectively. All these 
figures were outlined with the camera lucida and details added in freehand. 
Fig. 29 was slightly enlarged by eye from a whole stigma. 
