74 RHODOSPERME^. 



is true that bodies supjDosed to be of the nature of stamens 

 (and called antheridia) are found on many Algae, but how 

 they act, or whether they act on the spore at all, has not 

 been ascertained. But granting that antheridia are stamens, 

 the analogical arguments now put forward in favour of spores 

 being seeds would be materially strengthened. For, in flow- 

 ering plants, with whose metamorphoses we have been com- 

 paring those of Algffi, we know that stamens and pistils are 

 modifications of a common type, altered for a special purpose, 

 and now assuming one form and function, now the other. 

 And in Polysiphonia we find both spore and antheridinni hav- 

 ing a common origin, both being a cellular growth of the 

 apical fibres or vamelli ; the spore being formed on the ra- 

 melli when the branch is metamorphosed into a conceptacle, 

 and the antheridium on the ramelli of the unchanged 

 branches and developed externally. 



These organs [antheridia) , supposed to be representatives 

 of the male system, have been observed in several genera. 

 They are especially obvious in Rhodomelace/E (Polysipho- 

 nia, Rhodomela, &c.), when they consist of minute, pod- 

 shaped bodies, full of yellow, vivacious granules, and borne 

 on the colourless fibres in which the branches and ramuli 

 terminate. In Laurencia the antheridia are contained in 

 cup-shaped bodies, resembling very open ceramidia, and oc- 

 cupying the place of those organs. 



The Rhodosperms are distributed in seven orders, as 

 follows : — 



SYNOPSIS OF THE ORDERS. 



7. Rhodomelace.e. Frond celhdar, areolated or articu- 



lated. Ceramidia external. Tetraspores in rows, 

 immersed in ramuli or contained in proper recep- 

 tacles [stichidia). 



8. Laurenciace.e. Frond cellular, continuous. Cera- 



midid external. Tetraspores scattered, immersed in 

 the branches and ramuli. 



9. CoRALLiNACE/E. Frond calcareous or crustaceous, ri- 



gid. Ceramidia external, containing the tetraspores. 



10. Delesseriace.e. Frond cellular, contimious, areo- 

 lated. Coccidia external. Tetraspores collected into 

 definite clusters (sori). 



