1912] YAMANOUCHI—CUTLERIA 487 



zoospore with the haploid number germinates with no fusion. The 

 product of the zoosporeling is a filamentous individual like young 

 Cutleria, and never produces the zonal flattened form of the parent 

 Aglaozonia. 



The condition in cultures is very different from the environment 

 in nature. In nature the gametes and zoospores are set free at a 

 depth of 1-5 meters and in cultures they are discharged and kept 

 in sea-water at a depth less than 15-20 cm. Besides, the intensity 

 of light, water-pressure, temperature, and motion of water are also 

 different in these two different environments, and yet the sporelings 

 of the fertilized gametes developed into the flattened disk like 

 young Aglaozonia and those of the zoospores grow into filamentous 

 plants like young Cutleria. That the potentialities of those two 

 kinds of sporelings in forming invariably the particular individuals 

 different from the parent forms as in nature, even under environ- 

 mental conditions so different from what is found in nature, and that 

 the potentialities of the two different sporelings have given rise to 

 the particular different individuals, even when they were kept in 

 similar cultures, show that the potential characters of their germ 

 plasm has dominated over the influence of environmental con- 

 ditions; this dominancy of the innate character over the environ- 

 mental influence is fundamentally different from the experiments 

 of Klebs on certain green algae (23). Although the two kinds of 

 sporelings from fertilized gametes and zoospores in the cultures 

 have not been kept growing to the stage of reproduction, yet it 

 seems safe enough to infer that the disklike expansion developed 

 from the sporelings of the fertilized gamete will be identical with 

 Aglaozonia as found in nature, and the filamentous structures of 

 the zoosporelings will be Cutleria. Thus Cutleria plants with 

 zoospores represent a gametophytic generation, and Aglaozonia 

 plants with fertilized gametes the sporophytic generation. These 

 two generations alternate in the life history of Cutleria. The two 

 generations, from the above observations of the cell organization, 

 are fundamentally different and could not be regarded as an example 

 of polymorphism in the sense of Oltmanns (35). 



The observations on the sporelings of the unfertilized gametes 

 and studies of their cell organization undoubtedly show that the 



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