334 
The antheridial'clu- 
position to that of the 
sporangia, namely in 
Fig. 254. a row of 1 to 6 on 
Callithamnion roseum. A, sporangia-bearing branch. B, . n 
sporangia situated on the outer side of the branch. 4, the upper side of the 
52:1. B, 80:1. pinnulæ, usually one 
on each cell, rarely 
two, one over the other. Sometimes, the undermost cell or cells 
bear no antheridial clusters, the formation of these beginning only 
at a higher level, or the row is interrupted by joints bearing no 
antheridial bush. The branchlets bearing these organs are usually 
unbranched, but it occurs sometimes that they are branched above 
and the case may also be met with that a cell of a branchlet 
bears a branchlet and an antheridial bush as well (fig. 255 C). 
The main axis of the antheridial cluster consists of five or six 
cells, which are usually shorter than their breadth. It is slightly 
curved towards the top of the branch and bears a number of 
Fig. 255. 
Callithamnion roseum. Antheridial clusters. A 205 : 1. 
B, C 560 :1. 
sters have a similar ~ 
Fig. 256. 
Callithamnion roseum. 
Procarp before fertili- 
sation. Only one auxi- 
liary mother-cell is 
present, a’, situated be- 
hind the carpogonial 
branch. 350 :1. 
