253 



1 



Further statements as to this species cannot be given owing to the very scarce 

 material at hand. 



The synonyms given are all dubious, as also mentioned by Foslie. The species 

 described by Heydrich resembles Foslie's species by 



the structure of the frond, but if his description is -fi^ 

 correct, it cannot be identical with it, and must even "^^^ 

 belong to another genus, as the conceptacle is said 

 to have as many openings as it contains sporangia. 

 Heydrich's description of the cortical cells also does 

 not agree with those of M. miimtula, as they are said ' 

 to cover^,lhe half of the cells of the disc; in M. nii- 



nutula they are very narrow, covering only a small " ■ -'M 

 part of the underlying cells. It must therefore be Fig. 173. 



concluded that Heydrich's species cannot be identified Mi^'obesia mmutuiu. Paitof trond with 



. . conceptacle. 200:1. 



With M. ininntula. 



The plant was found growing not only on the Bryozoan but also on Ceramiiim 

 tenuissimiim attached to the same Polgsiphonia. 



Locality. Ku: TP, Tonneberg Banke, 16 meters, September. 



6. Melobesia trichostoma sp. n. 



Frons primo monostromatica, dein, saltim maxima ex parte, polystromatica, 

 usque ad 8 cellulis crassa, plerumque tamen e pluribus lobis vel frondibus secun- 

 dariis minoribus, partim sese invicem oblegentibus composita, lobis plerumque usque 

 ad marginem polystromaticis. Cellulse frondis monostromaticae vulgo 7 — 8/^! crassse, 

 latitudine plerumque paulo longiores, cellulis corticalibus transverse ellipticis munitse. 

 Frons adulta e fills verticalibus composita, cellulis longitudine vario, latitudine 

 1 — 3-plo longioribus. — Conceptacula sporangifera verruciformia, parum elevata, 

 superne applanata, diametro 160 -280 //. Tectum planum, crassum, c. 5 cellulis 

 crassum. Ostiolum pilis numerosis, sursum longioribus, superioribus ex ostiolo pro- 

 minentibus ornatum. Sporangia tetraspora, 42 — 63 // longa, 17 — 29// lata. Concep- 

 tacula mascula non prominula, ostiolo in tubo longo, ssepe curvato, piotracto. 

 Spermatangia lineari-clavata in fundo piano conceptaculi e cellulis depressis pro- 

 creata, dense stipata. — Conceptacula cystocarpifera eadem forma magnitudineque 

 ac sporangifera et peristomio simili ornata. 



The specimens on which this species is founded formed dull rose-coloured 

 crusts on the shells of living Trochus cinerariiis collected in the Limfjord. They were 

 referred to Lithothamnion Lenormandi by Foslie in 1905 and are also rather like 

 old specimens of that species, especially the forma squamulosa. The frond is at first 

 monostromatic, and the marginal part may remain so, much resembling that of M. 

 Lejolisii, with well developed cortical cells, which seen from above are elliptical. 

 A parietal body, situated closely at the outer wall in these cells is very intensely 



