250 



The conceptacles of sporangia are proportionally higher than in M. Lejolisii, 

 hemispherical or subhemispherical, the height being frequently the half of the 



breadth. The cells surrounding the ostiole 

 are usually little characteristic, forming no 

 real peristome; they may be somewhat lengthe- 

 ned towards the opening, but take, as it seems, 

 scarcely the form of papillae, and do not as a 

 rule protrude outside the ostiolum. In some 

 cases, however, they are elongated, going out 

 in a prolongation of the surroundings of the 

 ostiole in a short spout, resembling that of 

 the antheridial conceptacles of M. Lejolisii and 

 M. limitata, but thicker (fig. 169 A). This 

 character, however, is not constant, being met 

 with only in some of the conceptacles but 

 wanting in others, usually most. When seen 

 from above, the ostiolum appears sometimes 

 surrounded by a rosette consisting, as it seems, 

 of very low papillae (fig. 168 D), in other cases 

 no such structure is to be seen. 4-parted spor- 

 angia were found in all the specimens exami- 

 ned, but 2-parted ones of the same size were 

 found in the same specimens. As I have 

 examined only dry specimens in which, as is well known, most of the sporangia 

 have been emptied by the desiccation, it could not be stated whether the 2-parted 

 sporangia were fully developed or not. I am inclined to suppose that 4-parted and 

 2-parled sporangia normally occur simultaneously. 



The antheridial conceptacles were usually not well preserved in the dried 

 material, but il could be seen that the spermatia were not produced at the end of 

 long sterigmata as in M. Lejolisii. In one case the ostiole was found prolonged in 

 a spout. 



The conceptacles of cystocarpia were smal- 

 ler than those of sporangia, and a little lower in 

 relation to their breadth ; the ostiole was simi- 

 lar in structure to these. 



The specimens growing on Polysiphonia ni- 

 grescens agree in all essential points with the 

 others; the cells of the monostromatic frond 

 were only a little broader, 9— 13/^. A number ^. 



Fig. 170. 



of the conceptacles were provided with a well Meiobesia i-osUei, from Bragerne. Vertical sec- 

 developed spout, containing elongated cells, the tion of frond with antheridial and cystocarpic 



" ' conceptacle. Below another section of the 



rest were without any projection. It appeared latter showing the orifice. 560:i. 



Fig. 169. 



Meiobesia Fosliei, from Tonncberg Banlte. A, verti- 

 cal section of sporangial conceptacle with orifice 

 prolonged in a spout. B, vertical section of cysto- 

 carpic conceptacle. 350:1. B 560:1. 



