Oogonium Literation and the Embryogeuy of Some Fucaceous Algae. 9 



Gystophylhnn^ for in living materials I liave very often had the 

 chances to observe the stage of oogonium development, in which 

 such cast off plasma-masses would likely be found, had they ever 

 been present, but I failed to find any trace of such a body. 



It is rather a curious fact that none of the foregoing observers 

 have succeeded in observing not only the fertilization but even 

 the moving spermatozoids in Sargasswii and Cijstophyllwn. Miss 

 Simons writes in her paper already cited that, "A study of 

 fertilization in Sargassum is surrounded by serious technical 

 difficulties, because both eggs and sperms develop upon the same 

 plant, thus making it difficult to isolate the sexual cells." As 

 above described, the common species of Sargassum and CystopkyUum 

 in our coast are all dioeceous, so the difficulty pointed out by Miss 

 Simons does not occur in our materials. Nevertheless the study 

 of the fertilization of these algae, both in living and fixed materials, 

 is not an easy task. I have never succeeded in observing even 

 the spermatozoid itself. From the phenomena of the periodical 

 development of the oosphères, one naturally presupposes the 

 periodical development of spermatozoids, but I could find no sign 

 of such a phenomena in the antheridia of these plants. 



Now let me give my observations on the development of the 

 sporelings of Sargassitm and Cystophylluin. The early development 

 of these algae goes on within the oogonia which after having been 

 discharged from the conceptacle, are attached to the surface of the 

 receptacle: this condition fascilitates the investigation in no small 

 degree. The later development may also be studied easily in 

 materials cultured in a glass basin. The method is very simple. 

 I collected some small branches of these algae which carried many 

 hundreds of attached sporelings on their receptacles and cultured 

 them in natural sea-water, some of the sporelings may in the 

 course of development fall to the bottom of the glass basin but 

 many remain attached to surface of the receptacle for a long time 

 and still persue the normal course of development. The detached 



