236 
perithallium seems to justify the distinction of the genus Epilithon. Another impor- 
tant generic distinction seems to exist in the position and development of the an- 
theridia, which in the genus Lithothamnion, as far as known, are not seriate, and 
always placed on a system of branched filaments filling the cavity of the conceptacle 
(see above pp. 213, 218). 
The species usually 
grows on Furcellaria fa- 
stigiata, but occurs in the 
Kattegat also on Chon- 
drus crispus, and has 
likewise been met with 
on Phyllophora rubens 
and Ph. membranifolia. 
It is rather common in 
the Danish waters within 
Skagen to the western 
Baltic Sea, but does not 
occur in the Limfjord 
(and in other fjords), and 
Fig. 155. = 3 
Epilithon membranaceum, vertical sections of cystocarpic conceptacles. À, sho- in the Sound it has only 
wing the orifice, B, showing carpogonia at the centre and carpospores at the been met with north of 
periphery. 350:1. 
Helsinger. It has been 
found in depths between 1 and 20 meters, and there is in this respect no difference 
between the different waters. Its absence in the Skagerak depends probably on the 
want of protection in this agitated water. 
Localities. Kn: Marens Rev, Deget a. o. locality near Frederikshavn; FF and FE, Trindelen, 
9—15 m; UB and TG, north of Læsø. — Ke: IM, Fladen, 16m — Km: XB, south of Kobbergrund; 
NV, off Randers Fjord. — Ks: FO, Havknude Flak; GG, Sjællands Rev, 4m; D; EJ, entrance to Ise- 
fjord: RL, near Ostindiefarer Grund, 15 m; OO, Søborg Hoved Grund, 8,5 m. — Sa: FT, north of Samsø, 
5,5 m; DK, Bolsaxen; AH and AH!, Lillegrund north of Fyens Hoved; MQ, south of Paludans Flak; AY, 
Ashoved. — Lb: AX, Bjernsknude, 9,5 m; north of Fæns Kalv; Fænø Sund; UX. at the north end of 
Ærø, 9,5 m. — Sb: DN, Vengeance Grund; Spodsbjerg; DT, off Magleby, Langeland. — Sm: Venegrund. 
— Su: BQ, off Ellekilde; off Aalsgaarde. — Bw: DU, off Dimesodde, 11,5 m;.UL, Øjet, 20 m; KZ. off 
Kramnisse, 4,5 m. 
Melobesia Lamour. emend. 
The extent of-the genus Melobesia has in course of time been repeatedly altered, 
certain species or groups of such having at various periods been detached there- 
from and referred to new or other previously known genera. Thus in 1889, SCHMITZ 
removed Melobesia Thuretii, and gave it the name of Choreonema Thurelii; in 1897, 
M. membranacea was established by HEyprıcH as representative of a new genus, 
Epilithon, related to Lithothamnion. FosLıE again, in 1898 (List of sp. p. 11) and 
1900 (Rev. Surv. p. 21) placed M. pustulata and some related species under a new 
