THE CHAROPHYTA 



383 



Manubrium 

 Shield 



Capitulum 

 Manubrium 



Basal nodal cell 



Flask cell 



Antheridial 

 filaments 



Fig. 366. — Chora fragilis. Section of a developing anther- 

 idium showing early stages of the spermatogenous 

 filaments. The flask cell is the uppermost basal cell. 



two or four terminal cells. From these terminal cells, as a result of repeated 

 division, two or four long filaments consisting of from 100 to 200 tiny cells 

 are produced. These are termed the spermatogenous filaments ; each 

 cell of the filament functions as an antherozoid mother cell, and from it 

 a single antherozoid is liberated (Fig. 367). The antherozoid is a small 

 spiral, rod-shaped structure with a single pair of flagella attached near the 

 apical end. The antherozoids are liberated by the falling apart of the shields 

 which form the antheridial wall, and the subsequent gelatinization of the 

 walls of the mother cells. 



The enormous production of antherozoids will be realised if we consider 

 that there are eight manubria in each antheridium, and that each manubrium 

 produces six capitula, which give rise to either two or four filaments of 

 spermatogenous cells. Taking the highest number in each case this means 

 the liberation of nearly 40,000 antherozoids from a single antheridium. 



It has been suggested, as has already been mentioned, that the antheridium 

 may really be a compound structure and that each cell of the primary octant 

 represents a secondary lateral branch of an antheridial axis, which divides 

 into three cells, the shield, manubrium and capitulum. Of these cells the 

 manubrium represents an internodal cell and elongates, as do such internodal 

 cells, while the capitulum corresponds to the basal node of the secondary 

 lateral and bears spermatogenous filaments, just as basal nodes in the vegetative 

 parts bear cortical filaments. Thus, by this interpretation, the cells of the 

 spermatogenous filaments may be regarded as single-celled antheridia 

 comparable to those in many Algae. 



