PIIYTOGKNESIS. 241 



My observations arc 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 arc 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 Char a vulgaris, I also observed their 

 development into cells in the sporules of Marchantia poly- 

 morpha, one of which, pushing the original wall of the sporule 

 before it, forms the long capillary root (pi. I, figs. 18-20). 



It is evident from the foregoing, that the cytoblast can new i 

 lie 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 laminae, 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 Blight 

 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 instanc 

 in the pollen-tube, which has become cellular in certain Orchid' 

 (figs. 16, 20). 



Meyen, who should always be consulted with reference to 

 anatomical questions, has endeavoured, in his Physiologic, vol. i, 

 p. 45, &c., 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 he 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. 



L6 



