256 M. Miiller on the Development of Chara. 



brane*, a secondary, which is easily separated from the latter, 

 and an internal more mucous one, in or upon which the true 

 cellular contents (gonidia of Kiitzing) are situated. The latter is 

 MohPs primordial utricle. When treated with nitric acid the 

 entire mass of the secondary membrane separates in an undula- 

 tory form (PL V. fig. 3). The contents of the cells, which con- 

 sist of a greenish granular mass, in this stage of the spores are 

 frequently absorbed at several places. The same occurs with the 

 above five terminal cells, the surfaces of which press so closely 

 together that there is no inlet into the spore (PI. VII. fig. 35). 

 The spore-sac is alone subjected to various alterations in form, 

 the spore always remaining oval. 



The sporular membrane is likewise a closed covering of a round- 

 ish-oval form, with a rounded summit and a truncated base 

 (PI. V. figs. 1. and 2), which flattens into a cell which will be 

 subsequently considered. It is uniformly thickened, and thence 

 cartilaginous, of a more or less brown colour, and has the same 

 spiral windings as the spore-sac. They correspond to one an- 

 other with tolerable accuracy, so that they are entirely or very 

 nearly in the same plane. This spiral plane turns from left to 

 right. The five extremities of these thickened, flattened cells of 

 the sporular membrane unite at the apex as in the spore-sac, with- 

 out forming any appendages. At the highest point the upper 

 portion of the windings projects somewhat at an acute angle 

 (Pl.V.%.6). 



The membrane of the nucleus lies close to the sporular mem- 

 brane, but quite separate. It of course depends on the form of 

 the sporular membrane, and differs from it merely in its more 

 delicate, transparent, uniform texture, which is neither cellular 

 nor spiral. 



The contents of the nucleus consist of starch-cells only ; these 

 vary in size and are of a more or less rounded, somewhat com- 

 pressed form. They are perfectly hollow, bursting either length- 

 wise or in the centre (fig. 5) to discharge their fine granulai* 

 contents, which also consist only of starch, as shown by the deep 

 blue colour produced by iodine, and which is not unfrequently 

 found between the parent-cells. By gentle pressure I was able 

 to force these contents from the parent-cells, but I have not been 

 able to observe this in loose pieces. 



As we have mentioned above, the spore is attached at its base 

 to 2i four-sided, tolerably large cell (figs. I and 2). This contains 

 a white, granular, densely aggregated substance, and whilst within 

 the spore-sac might be expected to perform some important part 

 in its nourishment. Moreover in it the nutritious fluid which 

 comes from the stem is rendered assimilable by the nucleus. 

 * See § <i, where this is coinparfcd to the cuticle. 



