from the Cell-contents of the Characese. 9 



cells ; but in no instance have I seen the former in the gonidial 

 cell, or been able to produce a blue colour in the nucleus of the 

 latter by the application of iodine. 



Thus we have followed the contents of the internode of Nitella 

 from the breaking up of the green layer to the development of 

 the gonidia. Let us now direct our attention to the different 

 parts of the gonidial cell analytically, more however with the 

 object of adding to rather than recapitulating what has already 

 been stated respecting it. 



We have seen that the mucus-investment, which appears to 

 be derived from the mucus-layer, gives the cell the power, not 

 only of limited polymorphism, but also of locomotion j in addi- 

 tion to this also, the cell possesses for some time the power of 

 projecting thread-like filaments of extreme tenuity from its sur- 

 face that adhere to neighbouring objects, and thus form a jwint 

 d^appui towards which the cell can then move itself. Subse- 

 quently, however, these processes, apparently following the same 

 law of development as the cell, become stiff, and then stand out 

 like short, straight hairs, more or less thinly scattered over its 

 circumference, and resembling a parasitic growth, — which some 

 might consider them, as they do not appear on all the cells, but 

 my impression is that they are what I have stated. I have also 

 seen, now and then, a small gonidial cell in which the hardening 

 process appeared not to be about to take place, but, from the 

 rhizopodous prolongations of a part of its periphery, and its con- 

 taining nothing besides the gonidial substance, presenting rather 

 the appearance of a polymorphic spore about to germinate than 

 to pass into a fixed cell. Occasionally the gonidial cell, after it 

 has become stiff and transparent, presents itself under a lenti- 

 cular form ; at others, as if a notch had been cut in it, and 

 sometimes with a plane surface, &c., but all these irregularities 

 appear to be caused by objects against which the cell rests while 

 passing from its flexible into its hardened cellulose state. Iodine 

 alone does not appear to impart any colour to the gonidial cell. 



Immediately within the transparent globular cell is a layer of 

 brown matter, which, as before shown, is composed of the green 

 disks in which the chlorophyll has thus become changed in 

 colour. This layer is also globular, and encloses the circular 

 disk alone or with its vesicle. It often presents a botryoidal 

 surface, which appears to be occasioned by the presence of the 

 gonidia inside or in the midst of its substance ; when the gonidia 

 have been developed, this as well as its granular contents disap- 

 pear, leaving a homogeneous, brown substance, which shrinks 

 up into a more or less defined nucleus of a much darker colour. 

 The brown matter is deepened in colour by the addition of 

 iodine, and extracted by that of alcohol. In the small gonidial 



