,„,vH>"*'/^'** %Q?'es in iSpirogyra. 295 



yAccording to this hypothesis, the contents of the filament-cells, 

 p/ the Spirogyr<B might form, sometimes a large immediately-, 

 germinating, single spore (fig. 1 a, b, c, fig. 5), sometimes several 

 parent-cells of moving spores (figs. 4, 8), and the contents o£- 

 already formed single spores might, instead of germinating im- 

 mediately, undergo metamorphosis into a number of propagative 

 cells equally capable of propagation (compare fig. 7. PI. VIII. 

 and Agardh's statement, page 211; Agardh having probably 

 seen the contents of the spores converted into the same moving 

 cellules which I found in the contents of the filament-cells) . This 

 apparently strange behaviour finds however its explanation, in 

 the fact that the Algse in general, as may be shown by reference 

 to similar phaenomena, are possessed of a greater variety oi forms 

 of spores than was formerly supposed. And that the form of the 

 propagative cell may vary between wider limits in these simple 

 plants, does not appear remarkable, when we reflect that the in- 

 dependence of the life of the individual cell is, of all plants, 

 greatest among the Algse, and that the capability of bringing 

 forth the same species is in them alone peculiar to the contents 

 of the individual vegetative cell. Why should this preserve only 

 in one, and not in more, persistent or transitory resting forms, 

 the reproductive power dwelUng in it? Can nature have here 

 connected the maintenance of the species with one single form, 

 where she yet has committed the power of reproduction pro- 

 fjisely to the mass of contents of each individual vegetative cell ? 

 ;; The very occurrence simultaneously of moving and motionless 

 spores in the same plant is but an expression of this possibility 

 of variation of form of the spores of the same species. For it is 

 untenable to attribute to the moving form a value different from 

 the motionless, and to call the moving germs, say propagative 

 gonidia, and the motionless true spores, since both correspond 

 in the same way to the universal law of formation of seed in true 

 asexual plants, to form reproductive cells by the immediate meta- 

 morphosis of the contents of the vegetative cells. But the capacity 

 of reproduction in the contents of the vegetative cells is not 

 connected merely with one single form of moving and one single 

 form of motionless spore, and in this especially is most distinctly 

 shown the great independence of the contents of the individual 

 cells of the lower plants. It is true that the contents of the^ 

 spore-mother-cells constantly assume a form of moving or motion?- ^ 

 less spore determinate for each species in the ordinary course of 

 the cell's life, and thence we see one propagate almost exclusively 

 by one definite form of moving spore, another almost exclusively 

 by one definite form of motionless spore ; but when the formation 

 of this ordinary, normal form, or the development of their already 

 complete normal form is prevented, the contents of the spore- 



