of Sphseroplea annulina. 91 



the spermatozoids of the Fucacese and Vauchericn give ground 

 for concladhig an analogous function, — I further succeeded in 

 demonstrating their fecundating 'power ^ by direct observation, with 

 an evidence such as can only be possessed by a fact of natural 

 science : there can be no doubt that the active bacilliform cor- 

 puscles are the spermatozoids of Sphceropleay and therefore the 

 cells in which they are formed must be denominated the anthe- 

 ridial cells. 



When the discharged spermatozoids have become diffused 

 through the water_, they are soon seen to assemble around those 

 cells of a Splicer oplea-^'dme,nt J the contents of which have become 

 metamorphosed into spores. They dance about in the vicinity 

 of these cells, attach themselves to the membrane, sometimes 

 tearing away again, soon to return. After a while a spermatozoid 

 approaches one of those little orifices, which we have already 

 noticed as perforating the wall of the sporangial cells ; here it 

 fixes itself and pushes the slender beak into the hole. The pos- 

 terior extremity is often too broad to pass in uninjured ; then it 

 screws itself forward with evident effort, the beak constantly 

 working its way, compressing the elastic body j finally it suc- 

 ceeds in forcing its way through and entering into the cavity of 

 the sporangial cell. In the mean time other spermatozoids have 

 slipped in through various orifices; frequently three or four 

 crowd at once into one orifice; the more slender corpuscles 

 make their way, at the first attempt, in a remarkable manner 

 swimming in wide curves, from the water, through the hole, 

 without obstruction, into the cavity of the cell ; after a time as 

 many as twenty spermatozoids circulating about in its interior 

 and ' swarming ' round the young spores. These, as above de- 

 scribed, are smooth spheres, more or less completely filled with 

 chlorophyll, surrounded by colourless plasma, without cellulose 

 membrane. The spermatozoids rush from one spore to another, 

 as if electrically attracted and repulsed, so rapidly, that the eye 

 can scarcely follow them ; they often swarm from one end of the 

 sporangial cell to the other ; now and then the spores are thrown 

 into slow rotation by the vibratile cilia of the spermatozoids, but 

 this is only accidental and inessential, possibly only when the 

 spores are in a very free position. I have seen the spermatozoids 

 moving about in the sporangial cell for more than two hours ; 

 gradually their motion becomes more sluggish, they become 

 adherent to the young spores, in such a manner that one or two 

 spermatozoids become fixed to each spore, cleaving firmly to it 

 with the beak and cilia, so that their body stands perpendicularly 

 upon the spore. In this position they oscillate backwards and 

 forwards for some time longer ; finally they come quite to rest 

 and apply themselves with their whole length against the sur- 



