JURANVI ON THE FERTILISATION OF CEDOGONIUM. 775 



where only two antherozoids had entered the central cell, the second only came 

 after the first had already laid for one and a half minutes on the central receptive 

 spot, and its anterior coils had been taken into the oosphere. It was not able to 

 displace this, and remained no longer fixed to the central spot after this first 

 antherozoid had been entirely absorbed, but remained, after swarming side- 

 ways for some time, lying on the oosphere. Of the first antherozoid no further 

 trace was visible after four minutes, the second became invisible only after thirty-five 

 minutes.' 



Juranyi describes the processes in the case of a species of (Edogonium—z. genus 

 of segmented filamentous Alg» — in the following words (Jahrb. fiir. wiss. Bot. IX, 

 pp. 7-19):— 



' After the swarmers have swarmed for from half an hour to an hour they come 

 to rest and fix themselves on the oogonia, or at least on the cells in its imme- 

 diate neighbourhood, and form unicellular dwarf males. The swarmers produced 

 by the antheridia-cells of the males are thus true androspores. The dwarf males 

 fix themselves generally 3-6 together round or on an oogonium, though cases 

 are by no means rare where they surround the female sexual organ in larger 

 numbers. Thus I have often seen oogonia surrounded by from twenty to forty or 

 even fifty dwarf males. 



' The antherozoids thus escaped behave in a very striking manner. Their 

 movement is not progressive, but a sort of twitching, or convulsive trembling, in con- 

 sequence of which they can only change their position clumsily and slowly. By this 

 means they describe a zigzag line around the oogonium, travelling in this way 

 until they have found the opening of the fertilising tube, or until they perish. — Since 

 these antherozoids are contractile to no small degree they continually change their 

 shape during the swarming; consequently they are seen sometimes as globular, 

 sometimes again as ovoid or as acuminate wedge-shaped corpuscles, which some- 

 times desist in their peculiar movements — as if they would come to rest — for several 

 seconds. When they remain free their movement may continue for two or three 

 hours. 



' When the antherozoid has discovered the opening of the fertilising tube 

 it meets with an obstacle which impedes its entrance to the oosphere ; for the size of 

 the antherozoid surpasses the width of the opening of the neck of the oogonium 

 so much that it could not freely slip through it without altering its size and 

 shape. To overcome this obstacle the antherozoids are aided by their extreme 

 contractility. Hence the antherozoid is seen to suddenly contract before the opening 

 of the neck of the oogonium, its form also changing at the same time so that its 

 anterior portion with the crown of cilia are directed forward towards the opening, 

 and it becomes wedge-shaped. The narrowed and pointed anterior portion of the 

 antherozoid is now slowly drawn in through the opening of the neck of the oogo- 

 nium, and as it enters it becomes more and more elongated at its anterior end, it 

 is at the same time very clear to see how the cilia of the corona move them- 

 selves vigorously like whip-lashes. This movement of the cilia continues only 

 until the anterior end of the antherozoid has approached so near to the surface 

 of the oosphere, that the cilia reach it, and, coming in contact with the soft 

 protoplasmic mass of the oosphere, remain attached to it. Here the antherozoid 



