114 
sometimes proportionally much developed (fig. 41), but like Kyrın I found it al- 
ways consisting of one layer of cells, while Prinesneim (Beitr. Morph. Meeresalg. 
p.26 Taf. VII fig. 2), BorGEsEn and Corıns (1906 p. 194) found it consisting of two 
or several layers. 
While this form in its typical shape is quite distinct from the typical f. lux- 
urians, intermediate specimens may sometimes occur. In my opinion it is a re- 
duced form of the species produced by growing near the low-water mark, where it 
may sometimes be exposed to the air. On the Danish shores it has only been 
found at the low-water mark, on the west coast of Jutland even at a higher level. 
It has been found growing on Porphyra umbilicalis, Sertularia pumila, Chetemorpha 
Melagonium and Polysiphonia nigrescens, in the months January to August. 
Localities. Ns: Esbjerg; groin no. 62 by Thyborøn. — Sk: Hirshals mole. — Lf: Hals. — 
Kn: Frederikshavn, harbour (!, TH. MORTENSEN, C. H. OSTENFELD). 
11. Chantransia Macula sp. nov. 
Thallus minutus membranaceus monostromaticus fere orbicularis, diametro 
usque c. 70, substrato adhaerens, initio parenchymaticus; dissepimentum primum 
medianum, sequentia obliqua; postea cellule marginales in fila repentia plus 
minus radiantia excrescunt. Cellule c. 4  crassæ, diametro sesqui- ad duplo 
longiores, chromatophorum stellare pyrenoide centrali instructum continent. Fila 
erecta sparsa brevissima paucicellularia simplicia plerumque e disco egrediuntur. 
Pili hyalini in filis radiantibus erectisque terminales hinc illine occurrunt. Spor- 
angia monospora in disco sessilia vel in filis erectis terminalia, ovata, long. 10— 
11,5 y, lat. 6,5—7 y. 
This very small species has been found growing on Polysiphonia violacea to- 
gether with several other species of Chantransia. It is very characteristic from its 
thin disc-shaped frond of an irregular outiine, approaching however the circular, 
and corresponding to the basal layer of the more developed species, while the erect 
filaments are wanting or much reduced. The germinating spore divides always by 
a median vertical wall, and oblique walls then appear in the two daughter-cells, 
frequently resulting in the formation of two inner, triangular and four outer cells 
(fig. 42 A, B, F). The orientation of the walls may be somewhat variable, but in 
the central part of the more developed discs one or two triangular cells are usually 
recognizable, thus indicating the place of the first division wall. In some cases 
one of the primary daughter-cells only is divided by oblique walls (fig. 42 D), and 
more rarely both cells are divided by a wall parallel to the first. The plant keeps 
for some time its parenchymatous character and a fairly regular outline, often up 
to the eight-celled stage, but then the marginal cells begin to grow out into creep- 
ing filaments which from the first may be rather irregular but later by the increa- 
sing number become more regularly radiating, forming a pseudoparenchymatous 
disc with irregular border formed by the separate ends of the filaments. The 
