Nov.,t9i6.j Y. KU WAD A. -SO ME PLCULTARITIKS OBSERVED. 351 



The fresh culture was usually made in the he^miun<r of 

 Aj)ril. A (Iroji of water of the old culture put. into the fresh 

 medium of 50' '" in volume was good enough after a few weeks 

 to make the latter appearing green with the organism, 'fhe 

 peculiarities of which I am going to describe were observed at 

 first when the climate became gradually hot toward the end of 

 June or at the beginning of July. In those hot days one may 

 encounter a downward motion of green mass of organisms in 

 columns from the surface of the culture water full of the or- 

 sranism either motile or non-motile to the bottom of the flask 

 (Figs. 2, 3) The. columns may sometimes reach the bottom, but 

 sometimes faint away before reaching the bottom. They may 

 sometimes unite with each other into a thick column and may 

 appear suddenly at a certain depth of water. The course of 

 traveling downward is usually vertical, but it sometimes tends 

 its direction to right or left. The downward motion is sometimes 

 slow and sometimes swift. By the aid of magnifying glass it 

 seems as if the innumerous swarmspores are falling down with 

 their o\vn weight producing an upw^ard current in the water 

 around the columns. But some of them are often found wander- 

 ing actively somewhere between those comraing down. In the 

 upward current some swarmspores are also found. Hence the 

 one comming downward and the other going upward. In the 

 latter case, however, the number of swarmspores is so small 

 that we can recognize their existence only b}- using the magni- 

 fying glass. It recalls Oltmanns' observations on Volvox. 



Here it is quoted'^: 



"Sofort nach der Bedeckung der Cultur beginnt eine Sortirung der verschiedenen 

 Tndividuen. Die Partlienogouidien fiilirenden begeben sich in den hellsten Theil des 

 Kaumes und sammeln sich in dichten Wolken nahe der liellsten Ecke an. Die 

 weiblichen dagegen, namentlich solche, deren Eier bereits befruchtet sind, bewegen 

 sioh melir in die dunkleren Regionen des Apparates (bei O, Fig. 1), sie bilden 

 hier keine wolkenartigen Massen wie die geschlechtslosen, sondern nach ganz kurzer 

 Zeit ordnen sie sich zu vertikalen Reihen an einer oder an beiden "Wiinden des 

 Gefiisses. Jede dersellien wird durch 20 bis 50 Tndividuen gebildet ; sie sind I'e- 

 Intiv lang an dein dunkleren Ende, kiirzer in dem helleren Tiieil des Gefiisses. In 

 diesen Reihen sind die Pfliinzchen durchaus nicht unbeweglich, vielmehr vollt'iihren 

 sie lebhafte Bewegungen in folgender Weise: Sie sind vertikal gestellt, der vordere von 

 Oogonien freie Theil zeigt nach oben, dem entsprechend der andere nacii unten. 



1) Flora. 75. 1892. p. 187. 



