1 8 Davis. — Spore Formation in Derbesia. 
gradually grow fainter and probably at last disappear. The nucleus of the 
germinating spore divides mitotically, the spindle being intranuclear. 
It is clear that the nucleus of Derbesia has very intimate relations 
to the development of the blepharoplast, and that the latter does not arise 
from the plasma membrane, but from granules associated with the proto- 
plasm investing the nucleus. These granules are not, however, centrosomes. 
Cambridge, U.S.A., 
March , 1907. 
Note : — Since the above was written there has appeared a paper by 
Escoyez (’07), ‘ Blepharoplaste et Centrosome dans le Marchantia poly- 
morphal La Cellule, xxiv, 247. This author, contrary to Ikeno (’03), 
finds no centrosomes in the mitoses preceding the differentiation of the 
sperm-mother-cells. Blepharoplasts, two in number, were first observed 
in contact with the plasma-membrane in the sperm-mother-cell and they 
occupy the poles of the spindle of the mitosis within this cell, which 
precedes the organization of the two sperm-nuclei. Escoyez does not 
consider the blepharoplast to be a true centrosome. He has not traced 
its origin, and we do not know whether it comes from within the cytoplasm 
near the nucleus or is formed in the plasma membrane. The former 
alternative is to be expected. 
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