236 



perithallium seems to justify tlie distinction of the genus Epilithon. Another impor- 

 tant generic distinction seems to exist in the position and development of the an- 

 theridia, Nvhich 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. membranifoUa. 

 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 

 in the Sound it has only 

 been met with north of 

 Helsingor. 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 ])rotection in this agitated water. 



Localities. Kn: Marens Rev, Deget a. o. locality near Frederikshavn ; FF and FE, Trindelen, 

 9—15 m; UB and TG, nortli of Lieso. — Ke: IM, Fladen, 16 m — Km: XB, south of Kobbergrund; 

 NV, off Banders Fjord. — Ks : FO, Havknude Flak; GG, Sjajllands Rev, 4 in; D; EJ, enti-ance to Ise- 

 fjord; RL, near Ostindiefarer Grund, 15 m; 00, Soborg Moved Grund, 8,5 m. — Sa: FT, north of Sams0, 

 5,5 m; DK, Bolsaxen ; AH and AH', Lillegrund noi tli of Fyens Hoved; MQ, south of Faludans Flak; AY, 

 Ashoved. — Lb: AX, Bjornsknude, 9,5m; nortli of F''a?n0 Kalv; Ften0 Sund; UX. at the north end of 

 JEr0, 9,5 m. — Sb: DN, ^'engeance Grund; Spodsbjerg; DT, off Magleb}', Langeland. — Sm : Venegrund. 

 — Su: BQ, off Ellekiide; off Aalsgaarde. — Bw: DU, off Dimesodde, 11,5 m; UL, 0jet, 20 m; KZ, off 

 Kramnisse, 4,5 m. 



A 



Fig. 155. 



Epilithnn nwinlirrinaceiim, vortical .sections of cystocarpic eonccptacles. yl.sho- 

 carpogonia at the centre and carpospores at the 

 periphery. .350:1. 



Willi' the orifice, B, .showing 



IVIelobesia 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 Thuretii; in 1897, 

 M. membranacea was established by Heydrich as representative of a new genus, 

 Epilithon, related to Lithothamnion. Foslie again, in 1898 (List of sp. p. 11) and 

 1900 (Rev. Surv. p. 21) placed M. pustiilata and some related species under a new 



