CONFERVOIDE^-E HETEROGAMY 



Opens at its apex and exudes a drop of Colourless mufcilage. The oogone 

 still contains, chlorophyll, and its protoplasmic contents contract into a 

 green oosphere. At the same time flask-shaped protuberances grow out 

 from adjoining cells, and these, becoming cut off from the parent- 

 cells by septa, are the antherids. The entire contents of each antherid 

 escape as a single ovoid antherozoid furnished with two very long and 

 slender cilia. Other species are dioecious, the antherids being producejd 

 on different individuals from the oogones. The antherozQids probably 

 pass into the trichogyne through its open apex, and thence into the oogone; 

 but the act of impregnation has not actually been observed hitherto. 

 The first result of the impregnation of the oosphere- is its investment 



Fig jqg,—Cole(lchteteildvinaiaA..'Br. ^, portion of fertile thaUus(x 350) ;, ok, anthend ic^, oogone : 

 "fi hyaline hair; z, antherozoid. B, ripe oogone with its perrca'rp, r'(x 280).- -C, formation af 

 C carpoiporCs within the spsrmocarp ( X 280). Z>, zoospores ( x 280). (After Pnngsheim.) 



by a cell-wall of cellulose, and a considerable increase in its size. The 

 fertilised oogone, with the . exception of, the trichogyne, then becomes 

 gurrounded \yj 2, pericarp , or cortical layer of cells ; the-oogone and peri;- 

 carp together constitute the spermocarp enclosing the fertilised oosphere 

 or oospernt. The spermocarp subsequently becomes further invested by 

 3, cortex of closely applied branches resulting from the continued de^ 

 yelopment of cells at the base of the spermocarp. After the complete 

 dfivelopifient of this organ, which takes place between- May and July, 

 the vegetative cells of the thallus disappear, and its walls assume a dark- 

 hrown colour. ■ The spermocarp remains dormant through the winter; 



