252 



tacles more resemble those of M. limitata, but Ibis species is more different prin- 

 cipally by the stronger development of the filaments surrounding the ostiole. It 

 much resembles M. minuiula Fosl. (comp. Foslie Remarks p. 107) from which it 

 differs by its more incrusted frond and by the usual presence of trichocytes. 

 Whether it can be kept distinct from it must be decided by further investigations. 



Localities. Sk : YN-, south-east of Bragerne, on Polysiphonia nigrescens and violacea, July; 

 Lenstrup, on Corallina nibens, washed ashore, June (C. H. Ostenfeld). — Kn: Within Deget near Frede- 

 rikshavn, on Cor. rub. (C. H. Ostenf.); north-east of Hirsholmene, 6 — 7,5 meters, August, (C. H. Ostenf.); 

 TL, north of Lccso, on Cor. rubens, Sept.; ZL', nortli of Ltesa, 9,5 meters, on Corallina officinalis, July; 

 TP, Tanneberg Banke, 16 met., on Cor. rubens, Sept. 



5. Melobesia minutula Foslie. 



Foslie, Algolog. Notiser, 1904, p. 8; Remarks, 1905, p. 107. 

 Lithoctjstis Allinanni Harvey, Phyc. Brit. Vol. 11, plate 166, 1849 (?). 

 Melobesia inaquilatera Solms, Corall., 1881, p. 12, Taf III fig. 13-18 (?). 



Non Epilithon Van Heurckii F. Hej'drieh in J. Chalon, Liste des Algues mar. obs. jusqu'a ce jour entre 

 I'embouchure de I'Escaut et la Corogne, 1905, p. 207, fig. 1—5. 



Foslie has referred to this species some specimens growing on Bryozoans 

 attached to Polysiphonia elongata collected by me in the northern Kattegat (comp. 

 Remarks p. 109). They form small, scarcely incrusted fronds consisting of a single 

 layer of low cells, irregular in outline but not lacunose, wherefore it has been re- 

 ferred to f. typica. The frond is monostromatic in its whole extent to the border 

 of the conceptacles. When seen from above, the cells are usually 7 — 10// broad, 

 of the same length or a little longer. Very small hyaline cortical cells are as a 

 rule present, covering the pericline walls. According to Foslie, they "mostly seem 

 to be wanting", which statement is probably founded on the fact that they are only 



discernible by rather high magni- 



fying powers, owing to their small 

 size and transparence. They are 

 narrower than in the other Me- 

 lobesise examined by me. They 

 were also found over the periclinal 

 walls situated under the pseudo- 

 dichotomies (fig. 172), a fact in ac- 

 cordance with the complete absence 

 of trichocytes. 



The snorangial conceptacles are 



Melobesia minutula. A, part of a frond seen from above, at right COIllCal-hemisphencal With a Small 

 the primar)' disc. The cortical cells have not been drawn in the orifice SUrrOUllded bv 3 whorl of 

 upper and under part of the figure. B, a tetrasporangium. 350:1. 



cells radiating towards it. I found 

 them about 90 /^ in diameter (fig. 173). The sporangia were found to be tetrasporic 

 (fig. 172 B), 43—54 /i long, 24—31 // broad. Foslie found them only disporic. — 



