ALG.E. 



447 



Keproduced by spores (E) formed in special sporangia, which are 

 either superficial or plunged in the frond, and contained within 

 special cavities or " conceptacles " (D) of varied form. The sporange 

 is provided with a special tube, or " toieihogyne" by means of which 



Fkr. 510. 



Oiganiz&tion of Khodospermeae : A. Pait of a thallus or frond of Laurencia pinnatifida. 

 B. A magnified fragment of a lobule with stichidia containing tetraspores like c, a more 

 magnified figure. 1). Lobule of the frond bearing ceramidia or spore-conceptacles : d, the 

 spores. E. Spores from the same, more magnified. F. Lobule of a frond bearing anthe- 

 ridia, a. 



it is fertilized by the antherozoid ; accompanied by antheridia (P), 

 containing a single motionless antherozoid without cilia, and by 

 tetraspores (B, c), collections of 4 cells formed in special parent 

 cells in similar situations to those of the spores. Illustrative 

 Suborders: Subord. 1. KHODOMELE.E : Mhodomela, Agh. ; Polysi- 

 phonia, Grev. Subord. 2. LAUEENCIE^ : Laurencia, Lamx. ; Ghy- 

 lodadia, Grev. Subord. 3. COEALLINE^E : Corallina, Tournef . 

 Melobtsia, Lamx. Subord. 4. DELESSERIEJE : Delesseria, Lamx. 

 Plocamium, Grev. Subord. 5. SPH^EOCOCCEJE : Plocaria, Nees 

 Splicer 'ococcus, Grev. Subord. 6. CRTPTOIVEMIE^ : PkyUopor*, 

 Grev. ; Chondrus, Grev. Subord. 7. CEEAMIEJE : Callithamnion, 

 Lyngb. ; Griffithsia, Agh. ; Ceramiwn, Adans. Subord. 8. POE- 

 Porpliyra, Agh. 



Structure and Life-history. In spite of the varieties of form presented in 

 this Order, there is so close an essential agreement in their organization that 

 they distinctly appear as members of one natural group, with characters 

 whose value is only equivalent to that of some of the subdivisions of the 



