36 



or ellipsoidal form and becomes filled with dark fine- 

 grained protoplasm; it contains a nucleus which, by 

 successive bi-partition becomes eight nuclei. Tha 

 protoplasm separates into eight portions with a 

 nucleus and a brown fleck in the middle of each (due 

 to the aggregation of colour bodies). These com- 

 pletely fill up the cavity and pressing one against 

 another, become polygonal. Each mass is an oosphere 

 or female reproductive organ. (It is analogous with 

 the ovum in higher plants). 



The wall of the oogonium consists of two layers, 

 the outer one splits, and the inner one protrudes in 

 the form of a sac, which becomes distended by 

 absorption of water ; in this enlarged sac the 

 oospheres become globular. The inner membrane 

 now splits and the oospheres are liberated as naked 

 balls of protoplasm, each of which has a central 

 nucleus and its colour bodies equally diffused. 

 At about the same time the Antherozoids are liber- 

 ated by rupture of the antheridium, they swarm in 

 large numbers round the oospheres, become attached 

 to them by their anterior cilia — if their number is 

 sufficiently great their movement is so energetic 

 that they impart to the oospheres a rotatory motion 

 which may last for half-an-hour. This phenomenon 

 is nowhere else exhibited in the vegetable kingdom, 

 though it is known in several genera in the animal 

 kingdom. Some of the antherozoids mingle their 

 substance with that of the oosphere, whose motion 



