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nuclear origin in the androcytes of Mnium; they fuse to form a spherical 
mass. Lewitsky (1911) figures a variety of dark-staining bodies in cells 
of Pisum and Asparagus, all of which he identifies as chondriosomes. 
He thinks that leucoplasts and chloroplasts develop from chondriosomes — 
a notion which is vigorously opposed by Meyer (1911) 1 ). Lundegard 
(1910) suggests that many of the above-mentioned structures, like similar 
objects which he has studied in the meristematic root-tip cells of Vicia, 
are leucoplasts, or in certain cases vacuoles, variously deformed and dis- 
placed by the action of fixing reagents. 
Whether or not Lundegard be correct upon this point, and what- 
ever homologies may exist between these different plant cell inclusions, 
or between any of them on the one hand and the chondriosomes or chro- 
midia of animal cells on the other, I find nothing in the published accounts 
to suggest that any of them are in any essential respect comparable with 
the kinetosomes. The possibility of coursc remains that a careful study 
of their origin, behavior and function may throw a quite new light upon 
the real nature of some of these cytoplasmic structures. 
One brief notice has appeared of structures which may at least be 
suspected of a homology with the kinetosomes of Polytrichum. Yama- 
nouchi (1908) finds dark-staining, elongated bodies imbedded in the 
cytoplasm of the primary androgone of Nephrodium. They seem, he says, 
to play no important part in connection with mitosis; but he did not 
study spindle formation. No such bodies appear in vegetative cells. In 
successive androgonial generations these structures, like the kinetosomes, 
become gradually less conspicuous and finally indistinguishable, though 
rarely visible as late as the sixteen-eell stage. Similar bodies occur in the 
central cell of the archegonium, and it is only in this cell that Yamanouchi 
figures them. They are here grouped opposite the poles of the division 
figure much as the kinetosomes are in the dividing androgones of Polyt- 
richum’, but this fact may be of little significance, since some such 
arrangement seems to be compelled by the shape of the central cell 
and the breadth of the spindle. 
I have referred the material of which the kinetosomes consist, 
tlius far without discussion of this particular point, to the dass of sub- 
stances designated as “kinoplasm”. Since the first application of this 
term by Strasburger (1892) to certain of the more active constituents 
1 ) Mcntion should be maile of the work of Pensa (1910), who likewise 
liolds that the mitochondria may develop into leucoplasts and chloroplasts, and of 
two recent papers by Guilliermoxd (1911a — b), who comes to a similar conclusion. 
