512 
comes only 3—5 cm high, undoubtedly owing to the slighter salinity; here, how- 
ever, it still produces ripe cystocarps. 
In May 1929 I found G. mamillosa in the harbour of Skagen forming a conti- 
nuous vegetation in the lover part of the tidal region and below the low-water 
mark. It was very well developed, reaching a length of 8,5 cm. There was a remark- 
able difference between the specimens growing over 
| and below the low-water mark; the latter were broad, 
A B 
Fig. 476. 
Gigartina mamillosa. Harbour of Skagen. A in the littoral zone, B at low-water mark. Photo, */, nat. size. 
of a proportionally bright colour, without or only with very feeble papillæ appearing 
as low warts, whereas the littoral specimens were much darker, nearly black, and 
bearing numerous long, partly branched papillæ, mostly near the border (fig. 476). 
The sublittoral specimens were perhaps a year younger than the littoral ones. 
Localities. Lf: Thisted, first discovered by J. P. Jacobsen in August 1869, later found by me in 
Sept. 1890 and August 1893; it grew on the moles and on a stony slope east of the harbour. — Kn: 
Skagen, harbour, discovered May 1929. (The harbour was built in 1904—1907). — Sa: Aarhus, 
discovered in 1911 or 1912 by V.Petersson on a stony slope at the bathing-place “Kattegat” north of 
the harbour. I found it in 1917 and 1927 in the same place and on the outer side of the North mole, 
but it did not grow on the southern mole (at least 20 years old). 
Phyllophora Greville. 
1. Phyllophora membranifolia (G. & W.) J. Agardh. 
J. Agardh, Alg. maris medit. (1842) p. 93; Harvey, Phyc. Brit. Vol. II (1849) pl. 163; J. Agardh, Sp. g. o. 
Vol. II, p. 1 (1851), p. 334; Wille, Bidrag (1885) p. 17, 32, 42, 65, 68, Tab. V, figs. 57, 58; Wille, Beiträge 
(1887), p. 79, Tab. VII, fig. 65; Buffham, Repr. Org. (1891), p. 248, PI. 16 figs. 10—13 (antheridia); 
