PHYTOGENESIS. 241 
My observations are much more limited with respect to the 
Cryptogamia; nevertheless, I found the cytoblasts in the sporidia 
of the Helvelloids, where, however, in consequence of their great 
transparency, they are only perceptible with a very strong 
magnifying power, and after the field has been much darkened. 
I have seen them in the large yellowish cells in the interior of 
the so-called anthers in Chara vulgaris. I also observed their 
development into cells in the sporules of Marchantia poly- 
morpha, oue of which, pushing the original wall of the sporule 
before it, forms the long capillary root (pl. I, figs. 18-20). 
It is evident from the foregoing, that the cytoblast can never 
he free in the interior of the cell, but is always enclosed in the 
cell-wall, and (so far as we can learn from the observation of 
those cytoblasts which are sufficiently large to allow of this 
very difficult investigation) in such a manner that the wall of 
the cell splits into two lamine, one of which passes exterior, 
and the other interior to the cytoblasts. That upon the inner 
side is generally the more delicate, and in most instances only 
gelatinous, and is also absorbed simultaneously with the cyto- 
blast (figs. 8, 16, 21). In making a section, they are some- 
times detached and scattered over the object, which might lead 
to the supposition that they lay free. It is probable also that 
subsequently, when absorption commences, they do become dis- 
engaged from their connexion with the cell-wall, and a slight 
touch may then be sufficient to move them from this position. 
The cell-wall is often considerably thickened in their neighbour- 
hood, especially when they are somewhat globular; for instance, 
in the pollen-tube, which has become cellular in certain Orchidee 
(figs. 16, 20). 
Meyen, who should always be consulted with reference to 
anatomical questions, has endeavoured, in his Physiologie, vol. i, 
p. 45, &ec., to establish the opinion, that the cell is formed 
of spiral fibres which lie closely one upon another, founding 
his view in a most ingenious manner upon his own beautiful 
observations on the relations of structure in fully-developed 
cells. My direct observation, which may easily be repeated 
by every one, shows, it is true, quite a different mode of forma- 
tion; I must, however, bring the facts related by Meyen into 
unison with my discovery, in order not to permit an apparent 
contradiction to remain unresolved. 
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