258 



that it should be referred to another genus; but as other characters justifying its 

 removal from tlie genus Melobesia are not known, I prefer to retain it under the 



genus provisionally. The small size of the tetra- 

 sporangia seems to be a significant mark dis- 

 tinguishing it from other species. The want of 

 transversal pores between the cells of the vertical 

 filaments, and the fact that these cells are not dis- 

 posed in transversal rows, exclude it from the genus 

 Lithophyllum. 



Only found once, growing on the frond of 

 Furcellaria fastigiata, with ripe sporangia, ripe an- 

 theridia and carpogonia in April. 



Locality: Sa : PP, Ryes Flak, 5 meters (no. 4670). 



Fig. 179. 



Melohcsia microspora. Vertical section of 

 female conceptacle; at left a carpogoni\im 

 from another section of the same concep- 

 tacle. 420:1. 



Choreonema Schmitz. 

 1. Choreonema Thiiretii (Bornet) Schmitz. 



Fr. Schmitz, Uebersicht, Flora 1889, p. 21 (reprint); id. in Engler u. Prantl, Nat. Pflfam. I p. 541; Fr. 



Minder, Die Fruchtentwicklung von Choreonema Thur. Diss. Freiburg, s. a. 

 Melobesia Tluiretii Bornet in Thuret, Etudes phycolog., 1878, p. 96, pi. .50, fig. 1 — 8; Solms-Laubach, 



Corallinenalgen d. G. v. Neapel, 1881, p. 12, 54, Taf. Ill fig. 1, 4—10. 

 Endosiphonia Thuretii Ardissone, Phj'cologia mediterranea. I. Varese, 1883, p. 451. 



This interesting Alga, parasitic in Corallina ruhens, has been met with in a 

 few localities in the Northern Kattegat and perhaps also in the Skagerak. Unfor- 

 tunately, the collected material was lost, except that from a single locality near Fre- 

 derikshavn; 1 must therefore content myself with referring to the quoted publications. 



Minder has in his important paper given a thorough description of the devel- 

 opment of the cystocarp, which in essential points modifies the statements of Solms- 

 Laubach. After fertilization, the zygote gives off short sporogenous filaments, which 

 gradually fuse with the auxiliary cells, but none of the numerous sporogenous 

 nuclei enter into these cells. From the marginal lobes of the resulting great sporo- 

 phytic cell (w^hich is not produced by mutual fusion of the auxiliary cells, but 

 has been nourished by them) the carpos{)ores are produced, becoming cut off by 

 watch-glass-formed walls. 



As I have had very few specimens at my. disposal, I cannot give any state- 

 ment as to the fructification in the Danish waters. 



Localities. Sk (?). — Kn: Within Deget near Frederikshavn (C. H. Ostenfeld), and perhaps a few 

 other localities. 



Lithophyllum Phil. 

 Subgenus Eulifhophyllum. 

 1. Lithopliyllum orblculatum (Foslie) Foslie. 



Foslie, Rev. survey (1900) p. 19 (without mention); Remarks (1906) p. 112. 

 Lithothamnion orbiculatum Foslie, Norw. Lithoth. (1895), p. 143, pi. 22 fig. 10 — 11. 



