Some Peculiarities Observed in the 

 Culture of Chf((iHf/(foinf)H((s, 



By 

 VosliiiiJiri Kuwaila. 



With Plate III. 



Now that the importance of the accurate knowledge of 

 the special morphology and physiology of plankton organisms 

 has become greatlj' esteemed, it would not be useless to report 

 here some observations and experiments made in the culture of 

 a marine species of Chlamydomonas, although the investigation 

 is owing to certain circumstances far from being complete. 



The material was secured in 1910 from the culture medium 

 of Phorphyra tenera. The medium was an artificial sea water^^ 

 of 3 m/8 concentration prepared after Van't Hoff's formula, 

 to which ammonium chloride was added to made up O.SVou 

 as the sourse of nitrogen. The organism propagated well both 

 in this medium and that containing potassium nitrate (I'Voo) as 

 the source of nitrogen. The other behaviors of the organism 

 were, however, quite different in the two cases. In the latter 

 case it propagated in the form of swarraspores and they showed 

 a beautiful phototactic reaction at the bottom of the flask on 

 the side away from the window'^ (Fig- !)• Whether this is due 

 to a negative phototactic nature of the swarmspores is rather 

 difficult directly to prove, but it is heighly conceivable that 



1) 3m/8 MgCl2 78<=<=- 



„ NaCl 1000 



„ MgS04 38 



„ KCl 22 



„ CaCl2 10 



2) The swarmspores used to swiiu near the surface of water for the first one or 

 two weeks forming the main collection at ihe side of the flask away from the window. 

 Then they sank to the bottom. Near the surface of water some collections were 

 also found at tlie window side, but no collection at the bottom on that side. 



