in Rhodymenia ies : 11 . Delesseriaceae. 185 
When the cystocarp occurs on the midrib of one of the 
ultimate forkings of the thallus, it is still smaller in proportion 
to the size of the thallus. It is only in this condition that it 
is figured by Harvey (’ 51 ). 
I have found the arrangement of the procarps to correspond 
closely to that already described as occurring in D. sanguined. 
The carpogonial branches are 4-celled, and arise on the 
pericentral cells above and below. They lean to the right 
and left alternately as in D. sanguined (Fig. 17). Of the four 
cells of the branch, the second is here too' by far the largest, 
exceeding in bulk the other three put together. The tricho- 
gyne is inflated where it reaches the surface, and protrudes 
but little. 
The next recognizable stage is elucidated by the same 
selective staining of the axial cell of the fertile joint, and of 
the six adjacent cells. At this stage the enlarged peripheral 
sterile derivatives of the pericentral cell are a conspicuous 
feature, although their appearance is dissimilar from the 
equivalent structures in D. sanguined. They consist similarly 
of two branches, but the posterior branch consists of only two 
cells, and the other branch of four (Fig. 1 8). These cells are 
relatively much larger than in D. sanguinea , and form a loose 
aggregate of cells, whose pit-connexion it is not easy to 
follow. 
The carpostome is formed by the over-arching of the 
surrounding vegetative filaments, though their growth seems 
to take place in a common mucilage and without any such 
invagination of the external surface as occurs in D. sanguinea. 
This is doubtless associated with the circumstance that 
the cystocarp does not attain the large size of that of 
D. sanguinea. 
The gonimoblast-filaments arise exclusively from an 
anterior derivative of the pericentral cell, and are directed 
forward in the early stage (Figs. 18, 19). There is the same 
probability that this derivative of the pericentral cell, rather 
than the pericentral cell itself, is here also the true auxiliary ; 
but the disorganization of the carpogonial branch at this stage 
