6 M. Tahara. 



receptacle in its first oogonium liberation: the black spots on the 

 receptacle are oogonia. The area in which the discharged oogonia 

 have already dropped off shows a remarkable contrast to the area 

 in which the oogonia are in situ in the conceptacle (Fig. 2, PL. 

 I). Fig. 3, PL. I shows the second oogonium liberation. The 

 older part of the receptacle becomes more slender and the surface 

 has the appearance of a young pine cone (Figs. 2, 3, 4, PL. I). 



The mode of oogonium liberation in Ci/stojûylhim sisymhrioides 

 differs considerably from that of S. Hoineri and deserves special 

 mention. The receptacle of Cijst. sisymhrioides is rather small and 

 slender and what is remarkable is that it shows no trace of 

 the conceptacle opening on its outer surface. As above stated 

 S. Horned has something like a plug at the conceptacle opening, 

 but the outline of the conceptacle opening on its outer surface can 

 be seen under the microscope without any difficulty; this however, 

 is not the case with Cyst, sisymhrioides. 



On the day before the oogonium liberation, paraphyses in 

 this alga begin to grow very rapidly. As there is no opening, 

 paraphyses must make their way through the outer wall of the 

 conceptacle. The tips of paraphyses peeping out through the 

 cracks on the outer surface of the receptacle are disposed quite 

 regularly in a line parallel to the main axis of the receptacle. 

 And in the mean time, the oogonium liberation takes place in the 

 same way as in Sargassim-, paraphyses continue to grow and 

 entangle with one another about the oogonia, giving an appearance 

 of a mycelium growing on a nutritive substratum (Fig. 1, PL. 

 III). As in the case of Sargasswn, the liberation at one time is 

 always restricted to a zone of receptacle, the liberation proceeding 

 acropetally. The discharged oogonia remain attached to the 

 surface of the receptacle for about five days and then drop off, 

 when the paraphyses protruded from the conceptacle and entangled 

 about the oogonia are also cleared away from the surface of the 

 receptacle.* 



* The protruded paraphyses are at first relatively stiff, but become gradually slushy. 



