THE MARINE ALGM OF NEW ENGLAND. 107 



trichogyne. After fertilization, the contents of the cell at the base of the trichogyne 

 divide, quadrant fashion, and we have a number of spores produced at once from the 

 original cell. In Xemalion the trichophore, or swollen base of the trichogyne, divides, 

 and the divisions grow out laterally and form short filaments, each cell of which becomes 

 a spore, so that at maturity the cystocarpic fruit consists of a dense tuft of radiating, 

 moniliform filaments. In the Ceramiece we have favellce, or cystocarps, in which the 

 carpogenic cells bud out and produce several lobes, each of which divides into a num- 

 ber of very short filaments, which do not separate from one another, but remain ad- 

 herent. The cells of the filaments are changed into spores, which form irregular 

 groups, but are still held together by the mass of jelly which surrounds them. In the 

 more highly developed suborders the spores either radiate in filaments from a sort of 

 placenta which is produced from the carpogenic cells or else are terminal on short 

 stalks. The pericarps are special sacks or conceptacles, inclosing the spores and 

 developed from the cells below the procarp, or we may have the cystocarps borne in 

 the interior of solid fronds, whose external portion may then be said to form a pericarp 

 around them. It will be seen that the structure of the Ftoridew is more complicated 

 than that of the other orders of algae, and the student cannot expect to obtain a clear 

 idea of the different suborders without considerable study. The following key will aid 

 somewhat, and the reader should consult the plates appended to this paper : 



1. Spores formed in the cells of the frond itself ..... Porphyrece. 



2. Spores (cystocarps) not formed directly from the cells of the frond, 



but from a special procarp - 3 



3. Spores without a special covering or pericarp , 4 



Spores with a special covering 10 



4. Spores naked 5 



Spores immersed in the frond 7 



Spores immersed in external warts 6 



5. Spores free on the surface of a lobulated mass Spermothamniece. 



Spores irregularly grouped in masses which are surrounded by a 



gelatinous envelope Ceramiece. 



6. Fronds erect, cylindrical . . . , Spongiocarpece. 



Fronds horizontally expanded Sqtiamariece. 



7. Spores arranged in dense tufts of radiating moniliform fila- 



ments Nemaliece. 



. Spores on an axile placenta in swollen branches . . » Gelidiece. 



Spores in numerous radiating tufts around a central placenta or 



carpogenic cell . . - Solieriece. 



Spores arranged without order 8 



8. Spores forming a single mass or nucleus and entirely buried in the 



frond 9 



Spores in several masses, separated by the tissue of the internal part of 

 , the frond and rising in swellings above the surface. . . Gigartinece. 



9. Fronds hollow and tubular JDumontiece. 



Fronds solid . .. Gryptonemiece. 



10. Spores arranged without regular order 11 



Spores in small, scattered tufts, borne on branching filaments — 



Hypnece. 

 Spores in radiating moniliform filaments 12 



