82 
situated directly on the basal dise or at the end of short unbranched erect filaments 
(fig. 42). An equally extreme reduction occurs in Ch. reducta, the frond of which 
consists of creeping filaments bearing sessile or short-stalked sporangia (fig. 49). 
In certain species the thallus is partly endophytic. In Ch. cylophaga the 
development begins as in Ch. polyblasta, and it is only when the plant has become 
multicellular that some of the cells in the creeping filaments produce short fila- 
ments from their underside, which penetrate into the cells of the host plant (Por- 
phyra umbilicalis), pushing aside the protoplasm and taking without doubt nutri- 
ment from it. This plant is thus a true parasite. The intracellular filaments or 
haustoria do not seem to penetrate from one cell into another but they may make 
their way again to the surface of the host plant (figs. 50, 51). In Ch. Dumontiæ the 
development begins in the same way but the endophytic filaments are intercellular 
and become much longer (fig. 52). These intercellular filaments are still more de- 
veloped in Ch. Nemalionis, where they form a widely extended system of branched 
threads, giving off free filaments at many points through the surface of the host 
(Nemalion), while creeping epiphytic filaments are wanting (figs. 53, 54). The ger- 
mination has not been observed in this species. Finally, there is a group of spe- 
cies the filaments of which are entirely endophytic. Ch. endozoica Darb. forms a 
transition to this group, the (endozoic) filaments sending out through the surface 
of the Alcyonidium it inhabits numerous short slightly branched sporangia-bearing 
filaments. In Ch. emergens only the solitary short-stalked sporangia are free (fig. 55), 
and in Ch.immersa and Ch. Polyidis the solitary sporangia are even more or less 
sunk in the host plant (figs. 56, 58, 60)". 
Most of the Chantransia are usually epiphytic and then not bound to parti- 
cular host plants; several species also occur on Hydroids and Bryozoa, further on 
Mollusc-shells, Ch. efflorescens even on stones. Probably other species may also 
sometimes grow on stones but have not been detected there on account of their 
small size. On the other hand, the endophytic species appear to occur only in 
one particular species of Algæ, or several nearly related. Thus, Ch. Dumontie has 
been found growing only in Dumontia filiformis, Ch. cytophaga only in Porphyra 
umbilicalis, Ch. corymbifera only in Helminthocladia, Ch. Nemalionis in Nemalion lu- 
bricum and multifidum, Ch. immersa in Polysiphonia nigrescens and violacea and 
in Rhodomela subfusca. The endozoic Ch. endozoica occurs only in Alcyonidium 
gelatinosum. 
The form of the chromatophore is of great systematic value as pointed out 
by Kyrın (1906, p.122). In the vast majority of Danish species the cells contain 
only one chromatophore, but these may again be divided into two groups. In a 
fairly large number of species the chromatophore has a central body lying in the 
1 Rhodochorton Brebneri Batters (Journ. of Botany 1897 p.437 and 1900 Tab. 414 fig.17), which 
is endophytic in Gloiosiphonia capillaris, is evidently a Chantransia belonging to this group, to judge 
from the mode of growth, the hairs and the chromatophore; its name must therefore be Chantransia 
Brebneri (Batt.) Rosenv. The genus Colaconema Batters (see page 71 note) seems also to comprise spe- 
cies referable to the group of the endophytic Chantransie. 
