ALGm. 



237 



the trichogyne replaces it. The lower swelling itself produces after fertilisation (ac- 

 cording to Bornet and Thuret) the cystocarp, numerous articulated branches sprouting 

 from it and forming a spherical ball (the Glomerulus), and the terminal members of this 

 produce the spores ; while beneath the trichogyne enveloping branches also arise (for 

 further details on Batrachospermum see Solms-Laubach in Bot. Zeitg. nos. 21, 22, 1867). 

 Thuret and Bornet found the most complicated and remarkable process of fertilisation 

 in Dudresnaya. Here the cystocarps arise on altogether different branches from the 

 trichophore ; after the long spiral trichogyne at their base has been fertilised, branches 

 shoot out from beneath it, which grow across to the fertile branches ; each fertile branch 

 has a spherical apical cell, and the ' tube connecteur ' applies itself closely to this cell and 

 afterwards continuing its growth becomes successively united with several other fertile 

 branches. At the points of union the articulated 'tube connecteur' coalesces with the 

 apical cell of the fertile branch, and the wall of both disappears. The part of the 

 ' tube connecteur ' which has thus conjugated swells up and becomes filled with proto- 

 plasm, which is separated by a wall and now produces the cystocarp. The ' tubes 

 connecteurs' thus convey the fertilising power from a trichogyne to the other fertile 

 branches, and produce cystocarps by conjugation with them. 



The act of fertilisation itself consists, in all Florideae, of a conjugation of the roundish 

 spermatozoid with the trichogyne ; /. e. the spermatozoid comes into contact with the 

 trichogyne, the wall becomes absorbed at the spot, and the contents of the spermatozoid 

 pass over into the trichogyne. This process of fertilisation takes place in the Nemahe^e 

 at the base of the trichogyne itself; in the Ceramiaceae and others in adjoining cells; 

 in Dudresnaya in altogether different branches by means of the 'tube connecteur.' While 

 the simpler processes in the Nemaliea? may be compared with corresponding processes in 

 ColeochcTte, the origin of the cystocarp of Lejolisia and Herpothamnion and of the more 

 robust Plorideae reminds one of the origin of the receptacle produced by fertilisation 

 in the Pczizse and Erysipheae among the Fungi ^ 



' [Porphyrese. Janczewski (M.'ni. de la Soc. Nat. dc Cherbourg, vol. XXI. p. 345, 1872, Ann. 

 des Sci. Nat. 1873, vol. XXII) describes the reproductive organs oiPorphyra leucosticta and P. laciniata. 

 In the former the frond, consisting of a single layer of cells, produces octospores by the division of the 

 contents of marginal cells. The octospores are set free by the softening and deliquescence of the 

 mother-cell-walls and of the septa between them. When free they are destitute of a cellulose investment, 

 and move by slow contractile changes of shape, only, however, very rarely putting out short pseudo- 

 podia. The octospores finally come to rest, develope a cell-wall, and germinate. The spermatozoids 

 are developed in cells like those which produce octospores ; there are usually however sixty-four from 

 each mother-cell ; they are spherical when free, destitute of a cell-wall, and without any mobility. 

 Occasionally a portion of the contents of a mother-cell is converted into octospores, and the rest 

 into spei-matozoids. Porphyra laciniata differs from the preceding species in being dioecious. The 

 segmentation of the contents of the mother-cells producing octospores is not, however, fully carried 

 out. The antheridial mother-cells only produce thirty-two spermatozoids. The protoplasmic contents 

 of the cells in the Porphyrece are coloured violet by iodine solution (with KI). The endochrome is a 

 mixture of chlorophyll and phycourythrine. Porphyrece appear to be connected with the Floridese 

 through the Dictyotex, all three agreeing in the immobility of their spermatozoids and spores (disre- 

 garding the amoeboid movements of the latter), but distinguished by their female organs, which are 

 quite distinct in the Dictyotex from those of the Floridece, and perhaps do not require fertilisation ; 

 while they are absolutely wanting in the Porphyrece, as far as our present knowledge extends.— Ed.] 



