272 



PART IV. CLASSIFICATION. 



The antheridia are small and unicellular ; in the simple fila- 

 mentous forms they occur singly or in groups at the ends of the 

 branches ; in others of more complex structure, they are produced 

 in special receptacles (e.g. Corallinacese) ; in the flattened paren- 

 chymatous forms they occur in groups on the surface ; in those 

 forms in which the shoot is differentiated into stem and leaf (e.g. 

 some Rhodomelacese such as Polysiplionia fastigiata and nigre- 

 scens, Chondriopsis tcnuissima) the antheridia are confined to 

 the leaves, the whole or part of the leaf being specially modified 

 for this purpose. The male cells (spermatia) are formed singly 

 in the antheridia, and are set free as 

 small, spherical or oval, unciliated cells 

 destitute of a cell-wall ; they acquire a 

 cell-wall at the time of fertilisation ; 

 they contain no chromatophores, except 

 in Bangiacese. 



The procarp presents considerable 

 variety of form and structure. It may 

 be unicellular (e.g. Bangiacese, Chan- 

 transia, Batrachospermum, Lemanea, 

 Nemalion), or multicellular, as is more 

 commonly the case. The unicellular 

 procarp consists simply of a carpo- 

 gonium prolonged (except perhaps in 

 Bangia) into a filament termed the tri- 

 chogync. Various descriptions are given 

 of the structure of the multicellular pro- 

 carp ; however, it appears to consist 

 essentially of a unicellular carpogonium 

 (with a trichogyne) together with one or 

 more specially differentiated auxiliary 

 cells. In some cases (e.g. Dudresnaya 

 coccinea, Squamariacese), the carpogonium and the auxiliary cells 

 are not developed in the same procarp, but in distinct organs. 



Whether the procarps be unicellular or multicellular, the carpo- 

 gonia agree in that the trichogyne remains closed, and further, 

 in that the protoplasm of the carpogonium does not undergo re- 

 juvenescence to form a distinct female cell (oosphere) as is the 

 case in the oogamous Algae (see p. 241). 



The carpogonium is (except in the Bangiacese) developed from 

 the terminal cell of a lateral appendage; in some cases (e.g. 



FIG. 159. Portion of a branch 

 of Dosya elegans, bearing a 

 slichidium (), with tetrahedral 

 tetrasporangia (t); V empty 

 tetrasporangium. (x 25 ; 

 after Kutzing.) 



