No. 374.] PLANT MORPHOLOGY AND PHYSIOLOGY. 101 
first surrounded by very numerous radiating filaments of kinoplasm. 
The division of the generative cell results in the formation of two 
antherozoid cells, one blepharoplast being contained in each. During 
this division the blepharoplasts, which have previously lost their 
radiating filaments of kinoplasm, burst, and the outer membrane of 
each becomes gradually extended into a narrow helicoid spiral band, 
from which the motile cilia of the antherozoids are developed. In 
fecundation this ciliiferous band, formed from the blepharoplast, is 
left intact at the apex of the archegonium, the nucleus alone taking 
part. No bodies resembling centrosomes have yet been found in the 
divisions resulting in the formation of the pollen grain or in the 
divisions of the egg nucleus after fecundation. 
In conclusion it was stated that the blepharoplasts resemble cen- 
trosomes: (1) in position, being located on opposite sides of the 
nucleus near the poles of the future spindle; (2) in having the kino- 
plasmic filaments focused upon them during the prophases of the 
division of the generative cell. They differ from typical centrosomes, 
however: (1) in arising de novo. in the cytoplasm; (2) in growing to 
comparatively enormous size; (3) in not forming the center of an 
aster at the poles of the spindle during karyokinesis; (4) in having a 
differentiated external membrane and contents; (5) in bursting and 
growing into a greatly extended cilia-bearing band, the formation of 
which is evidently their primary function; (6) in their non-continuity 
from cell to cell. The conclusion reached by the speaker was that 
in our present understanding of centrosomes the blepharoplasts must 
be considered as distinct organs. 
Dr. ROBERT A. Harper: Spore Formation in Some Sporangia. 
Protoplasmic cleavage and spore formation in types from the genera 
Synchitrium, Pilobolus, and Sporodinia were described. The division 
of the multinucleated. sporeplasm is neither simultaneous nor by 
repeated bipartitions, but is accomplished by the progressive growth 
of narrow cleavage furrows from the surface inwards. In Syachitrium 
decipiens this results in the formation of uninucleated spores, which, 
by subsequent division of their nuclei, become the resting zoösporangia 
of this species. In Pilobolus crystallinus a similar progressive cleavage 
produces oval or sausage-shaped masses, which have one or several 
nuclei. These nuclei now divide, and the plasma masses in which 
they are also divide by constriction, thus forming ultimately the 
definitive binucleated spores. In Sporodinia the process is much 
abbreviated, the primary cleavage furrows simply dividing the proto- 
plasm into relatively few and very unequal multinucleated masses, 
