189 
often been confounded with other species. It was only by becoming acquainted 
with the recently published description of Peyssonnelia (Cruoriella) Nordstedtii Weber- 
van Bosse! and by the final revision of my material that I arrived at the conclu- 
sion that it was not idenlical with the former, but more resembled Ihe last named 
species. As it proved to be different also from this and did not appear to agree 
with any other well known species, I describe it here as a new species. 
Cruoriella codana has only been met with once on a calcareous stone much 
bored by worms. It forms thin crusts of a bright purple colour, brighter than in 
Cr. Dubyi, and is adherent to the substratum in its whole extent, being fixed to it 
by unicellular rhizoids. The greatest crust is more than 5 cm in diameter, but it 
has probably arisen by coalescence of several distinct crusts; the other were at 
most 1 cm broad. When seen from the underside, the young basal layer appears 
composed of distinct lobes, which coalesce laterally. The lobes have a flabellate 
structure. Even when having a continuous outline, the margin is composed of very 
distinct lobes (fig, 112 A), and the same structure is found in the older parts of the 
hypothallium, where there are no principal rows of larger cells, as found in P. 
Boergesenii and P. Nordstedtii by Mrs. WEBER-VAN Bosse (1. c. p. 138 and 140). The 
cells of the basal layer are 14—33 long, 9—14y broad and 9—11y high. Uni- 
cellular rhizoids, bounded by a cell wall, are given off from its under face. The 
marginal cells of the frond divide by vertical cell-walls, and the segments divide 
immediately by a horizontal wall, the hypothallic cell becoming thus lower than 
the marginal cell (fig. 114). The monostromatic basal layer or hypothallium is only 
little distinct from the “perithallium” consisting of the vertical filaments given off 
from it. These filaments are vertical in their whole extent or slightly ascending; 
they are only rarely branched. The cells are of almost equal breadth in the same 
filament, 9—12 y, or the undermost may be a little broader. Their height is as a 
tule a little less than the breadth, near the surface sometimes much less, more 
rarely the same or a little greater. The number of cells in the erect filaments 
usually varies from 3 to 10. 
Old crusts are composed of two or more fronds growing one over the other. 
At first observation these superposed fronds might be supposed to come into exi- 
stence in the same way as recently described by Mrs. WEBER-VAN Bosse in Peys- 
sonnelia (Cruoriella) Nordstedtii (1. c. p. 141, fig. 146), by the formation of a horizontal 
split in the frond and following constitution of the part situated over the split as 
a new crust with a new-formed hypothallium. I have seen several cases which were 
favorable to this interpretation, in particular some apparently young cases and such 
where the under face of the upper crust was very irregular, and I might suppose 
that the new upper frond may really arise in this manner. But in other cases it 
is without doubt that the upper frond arises from horizontal outgrowths from certain 
parts of the crust which have preserved their growing power, while the covered 
! Rhizophyllidacez in F. BORGESEN, Rhodophyceæ of the Danish West Indies, Dansk Botan. Arkiv, 
Bd. 3. Nr. 1, 1916, p. 140. 
