On the Germination of the Spores of Ferns. 341 



while the other is attenuated. The author in some cases di- 

 stinctly detected a long filiform appendage, like that described by 

 Meyen in the Charas. The thickened end is sometimes quite 

 clavately thickened. When the filament is clearly seen, it is evi- 

 dently a band with a flat surface applied against the wall of the 

 cellule. The bursting of the cellules allows the filaments to 

 escape, but sometimes the whole or a fragment remains adherent 

 to it and is carried about by it. While the spiral filaments are 

 contained in the cellules in which they are produced, the convo- 

 lutions are closely approximated ; as soon as they become free, 

 they generally extend themselves and become like the turns of a 

 screw. 



When the cellules are evacuated from their sac, they often lie 

 from one to ten minutes unmoved ; then some of them begin to 

 move. At first they turn around their own axes without change 

 of place. As yet nothing is seen of the emergence of the spiral 

 filament. By degrees they begin to move from their place, at 

 first slowly, then more and more rapidly. The cellule still con- 

 tinues to rotate on its axis. Next, a portion of the filament is 

 seen to protrude from the cellule, which then tears quite open, 

 and the filament thus comes in contact with the water in its en- 

 tire length. . The motion is then considerably accelerated. The 

 cellules frequently begin to move directly they emerge from the 

 sac ; sometimes they rotate while still inclosed in it and before 

 it has opened; this happens when they are not in very close 

 contact. 



M. Nageli describes five or six kinds of movement of the spi- 

 ral filaments which he endeavours to define mathematically, but 

 he states that besides these, the motion often appears quite irre- 

 gular, especially in being suddenly arrested, diverted to one side 

 or reversed. But he does not consider these irregularities beyond 

 what may be accounted for by interfering influences occurring 

 in the fluid. He considers the motions as by no means volun- 

 tary ; being much too regular and mechanical for this. He says 

 also that a careful comparison of them with those of the Infu- 

 soria shows that they are totally different. 



The fundamental type of the movement of the filament is the 

 revolution round the axis, as Schleiden (Grundz. der Wiss. Bot.) 

 has explained it in the rest of the Cryptogamia. That this revo- 

 lution round the axis is proper to it as a primary peculiarity, 

 free from the other motions, is shown by these round and closed 

 cellules, which, with their inclosed filament, revolve merely 

 around their axis in water, or even while still within the organ 

 of the plant. This peculiarity must, from the fact, be at once 

 attributed to the spiral filament ; all the other movements may 



