160 



THE ANTHERIDIUM. 



The antheridinm of Ophiogiossum has been figured by Met- 

 TENius, Bruchmann and Lang. It closely resembles that of the 

 eusporangiate ferns, and also is much like that of Equisetum 

 and Lycopodiura. As in all of these, it is sunk deeply in the 

 tissue of the prothallium, only the opercular cell and its imme- 

 diate neighbors being free. While very young it lies flush with the 

 neighboring cells of the prothallium, l3ut later may become 

 more or less elevated above the surface forming a low^ promi- 

 nence which in slender prothallia like those of 0. moluccanum 

 may give an irregular outline to the branch which bears them 

 (Fig. 43). In 0. pendulum this is less marked, but in this 

 species also there may be a decided projection of the ripe 

 antheridium. The first division in both archegonium and anthe- 

 ridinm is periclinal and separates the primary cover cell from 

 the inner cell which in the antheridium, by further division, 

 gives rise to the spermatocytes. All the species appear to 

 agree closely in the development of the antheridium. There is 

 more or less variation in the form of the mother cell which 

 is sometimes comparatively broad and shallow (Figs. 62 — ^0), 

 sometimes deep and narrow (Fig 68). In the latter case the 

 primary cover cell is deeper relatively than in the former. Of 

 the two primary cells the innei' one is larger and has a corres- 

 pondingly large nucleus, but otherwise there is little difference 

 between them. Very soon, however, the protoplasm of the inner 

 cells becomes more granular. 



The first division in the inner cell is not always the same. 

 Bruchmann does not state what its position is in 0. vulgatum, 

 and my material of 0. moluccanum was too scanty to determine 

 whether the vertical position shown in Figure 63 is constant 

 or not. Lang states that he found this to be regularly the case 

 in 0. 2)endulum, and the writer has frequently found this to 

 be true in that species, but not uncommonly the first wall in 

 the inner cell of the antheridium may be transverse (Fig. 68). 

 The second walls intersect the first at right angles, and there 



