172 DopGE: RELATIONSHIPS OF FLORIDEAE AND ASCOMYCETES 
of carpospores. In certain species, such as Dermonema dichotomum 
(Schmitz 81), the sporogenous filaments form a complex system 
which develops wholly within the thallus, producing numerous 
clusters of carpospores separated by sterile tissue (Fic. 6, B). 
There can be no question in these forms as to the essential facts 
of their sexual reproduction. It has been described in Nemalion 
(Wolfe, 93) and in Batrachospermum (Osterhout, 69). The 
spermatium nucleus penetrates the trichogyne and passes down 
to the carpogonium where it unites with the egg nucleus. 
The remaining four groups, Gigartinales, Rhodymeniales, 
Ceramiales, and Cryptonemiales, in which a conjugation between 
the outgrowths of the carpogonium and an auxiliary cell occurs, 
do not differ materially among themselves for the purposes of our 
discussion, except perhaps as to the time and place of the develop- 
ment of the auxiliary cell, this cell being most closely connected 
with the carpogenic branch in the Gigartinales, while in the 
Ceramiales it may be entirely independent of, but paired with, the 
branch which bears the egg cell. In the former we have a second- 
ary fusion of a very simple type. Sturch (87) has described the 
formation and development of the procarpic branch of Harveyella 
mirabilis. This species is parasitic upon one of the larger red 
algae and is interesting to us because of its lack of chlorophyll. 
The curved carpogenic branch is composed of four cells and a 
basal cell which functions as an auxiliary cell. This is a large 
cell well supplied with nourishment. After fertilization and after 
the trichogyne has been cut off by a septum, as claimed by Sturch, 
the carpogonium grows out into a slender filament which unites 
with the auxiliary cell below, and from this a central cell is formed 
which gives rise to sporogenous hyphae (Fic. 4, E). The process 
in such a case in which the cells below the egg become involved 
by secondary fusions in the development of a spore fruit may be 
more similar to that in the lichens, Ascobolus carbonarius, etC- 
where we have the ascogenous hyphae developing from cells far 
back from the trichogyne, than has hitherto been supposed. The 
breaking down of the cross walls of the ascogonium in the lichens ° 
(Baur, 8, 9; Darbishire, 32; Bachmann, 3) and the formation of 
pores in the cross walls in the ascogonia of Ascobolus (Harper, 50); 
Ascophanus carneus (Cutting, 27), and Lachnea cretea (Fraser, 44); 
