128 DECAISNE AND THUKET. [BOOK i. 



from what has been observed in the Fucus, but then a Fucus is 

 itself very different from a Moss or a Liverwort. To those who 

 say that these corpuscles are sporidia, we have only to answer, 

 that this opinion, far from being supported by any direct proof, 

 seems altogether incompatible with the extreme smallness and 

 simplicity of the structure of these bodies. As to the hypothesis 

 that they unite together to form a propagulum, this is alto- 

 gether a piece of imagination that is not confirmed by a 

 single observation. On the contrary, these corpuscles seem 

 to be rather quickly decomposed, and form, at the bottom 

 of the vessel in which they are collected, a layer of inert 

 granules which soon disappear entirely. It is almost super- 

 fluous to add that we have never discovered any appearance 

 of germination.* "We think, on the whole, that we shall not 

 be far wrong if we regard these vesicles, so improperly called 

 microphytes, as analogous to the antheridia of other Crypto- 

 gams, but we cannot for a moment admit that these vesicles 

 perform the functions of sporangia, or the corpuscles those of 

 spores or sporidia. 



"The female receptacles are distinguished by their olive 

 colour. If they are examined when the plants are left dry 

 by the receding tide, their spores will be seen to come briskly 

 out of the conceptacles, and form, at the orifices of the latter, 

 little heaps which soon fall on, and remain attached to, the 

 neighbouring substances. If a thin slice is then made, the 

 conceptacles will be found to be covered with a more or less 

 considerable quantity of empty perispores, the diameters of 

 which seem to be less than those of the spores themselves. 

 The opening of the perispore, especially, is at times so narrow 

 that we cannot imagine the spore to have passed through it 

 without supposing it to possess great contracting powers. 

 The spore is as yet simple, although it presents well-marked 

 traces of its approaching division. The membrane by which 

 it is covered, at first thin and refracting, soon distends into a 

 transparent epispore covered all over with ciliee just like that 

 of the spores of Vaucheria : but it differs from the latter in 

 the spores of no Fucus having ever been seen, by us, to move. 



" An extremely curious phenomenon is now manifested ; 



* For the supposed nature of these and all such corpuscles, see Vol. I. 



