390 
erect filaments (fig. 327) or on lateral branches. The lateral branches bearing an- 
theridial clusters are short-celled. The antheridial clusters consist of short, recurved 
filaments composed of short, rounded cells and bearing on their convex side a 
small number of one- or two-celled short branches bearing together with the main 
axis of the cluster anumber of antheridia on the upper side and giving to the cluster 
a corymbose appearance. The antheridia are ovate, 6—7 w long, 4—5,5 w broad; they 
contain a rather large nucleus. As these organs have only been observed in specimens 
conserved in alcohol, their colour could not be ascertained, but they seem to contain 
no chromatophores. | 
Female sex organs have not been observed. 
The species has been found growing on Phyllophora membranifolia, Ph. Brodiei 
and Ph. rubens, further on the chitinous membranes of Tubularia sp. and Abielaria 
abielina, in 5 to 25 meters’ depth. 
A membrane agreeing exactly with the basal layer of this species, but without 
erect filaments, was found growing on a specimen of Cladophora rupestris gathered 
near Kerteminde. — The species was found with sporangia in May, June, September 
(unripe) and November. 
Localities. Kn: Near Hirsholm, 11 met.; Nordostrev by Hirsholm. — Ke: IT and EV, Groves 
Flak, 23—25 met.; IQ, Fladen. — Ks: Nakkehoved, 22. Nov. 1827, (Lyngbye). — Sa: MS, south of 
Klophagen, 15 m. — Lb: North of Fæno Kalv, 13 m; off Stenderup; dQ, bank south of Lyo, 22 m. — 
Sb: LL, off Brolykke by Kerteminde, on Cladophora rupestris, without free filaments; determination 
uncertain; UH, east of Langeland. — Bw: cE, Middelgrund south of Als, 13—15 m. 
Rhodochorton seiriolanum Gibs., described in 1890 by Harvey Gipson (Journ. Linn. Soc. 
Bot. Vol. 28, p. 204) has a monostromatical layer resembling that of Rh. penicilliforme. In a 
specimen of the same species from the Fsröes kindly communicated to me by Dr. F. BORGESEN 
I found that the cells contain one single chromatophore with a thick central portion in- 
cluding a pyrenoid. The species must certainly be referred to the genus Chantransia (Acro- 
chetium). 
2. Rhodochorton Rothii (Turton) Nägeli. 
Nägeli, 1861, p. 356, Taf. I Figs. 1, 3; Reinke, Algenfl. westl. Ostsee, 1889, p. 22; H. Gibson, Developm. 
of the sporang. in Rhodochorton Rothii. Journ. Linn. Soc. Bot. Vol. 28, 1891, p. 201; Kuckuck, 
1897, p. 20, fig. 5 (cell contents); Børgesen, Mar. Alg. Fzerées, 1902, p. 390. 
Conferva Rothii Turton, System of Nature VI, p. 1806 (teste Dillwyn); Dillwyn, Brit. Conf., 1809, plate 73. 
Callithamnion Rothii Lyngbye, Tent., p. 129, Tab. 41 A; Hornemann, Flor. Dan. tab. 2261, 2—3; Harvey, 
Phye. Brit. Vol. I, 1846, Plate 120 B; J. Agardh, 1851, p. 17; Kützing, Tab. phye. Vol. XI, 1861, 
pl. 62 I. 
Thamnidium Rothi Thuret, in Le Jolis, Alg. mar. de Cherbourg, 1861, p. 111, Pl. V. 
This species occurs frequently in the littoral zone where it forms purple velvety 
patches e. g. under the Fucus bushes. These patches consist of creeping filaments 
from which arise erect filaments which are usually without branches below. The 
creeping filaments may be composed of short inflated cells (fig. 328) or they may be 
thinner, composed of rather long cells (fig. 330). The erect filaments are usually given 
