usually two or more crowded together. Only in the dwarfed plant represented in 
fig. 18 D have I seen the antheridia situated directly on the filament, but in this 
case the filament was only two-celled. The juvenile stages of the epigynous an- 
theridia show that these antheridia are really terminal, while the trichogyne rises 
as a lateral outgrowth from the subterminal carpogonium (fig. 18 E, H), a case hith- 
erto unknown among the Floridee. I have repeatedly, in material preserved in 
alcohol, observed a little globular body lying immediately outside an empty anthe- 
ridium or at a slight distance from it (fig. 18 F, D); as it agreed in size with the 
spermatia adhering to the trichogynes (fig. C, K, L), I have no doubt that they were 
really spermatia. Probably a spermatium is often transferred from an epigynous 
antheridium to the trichogyne of the supporting carpogonium. After fertilization 
the ventral part of the carpogonium grows out into a slightiy inwards curved fila- 
ment which becomes 3-celled. The trichogyne is pushed outward so that it be- 
comes situated on the convex side, on the second cell of the filament (fig. C). The 
two lowest cells give off several branches, while the uppermost cell produces a 
carpospore (fig. C). Possibly the primary filament of the gonimoblast may some- 
times consist of more than three cells. The lateral branches obtain a different 
length, some becoming relatively long, articulated, curved and branched, others 
remaining short and in part apparently unicellular, producing a carpospore without 
division. The mother-cells of the carpospores have about the same form and size 
as the sporangia. The trichogyne or the lowest part of it can be seen long after 
fertilization on the second cell of the main filament; even in mature cystocarps a 
slight remnant of it is sometimes to be seen, (fig. A). The emptied epigynous an- 
theridium is also often to be found some time after fertilization; it is then situated 
on the first cell of the main filament (fig. J, K). 
While the plants often attain a length of 200 », very reduced plants also 
occur, consisting of very few cells (fig. D, E). In the plant shown in fig. E there 
was only developed one filament consisting of one cell only, bearing a hair, a car- 
pogonium with epigynous antheridium and a lateral outgrowth the character of 
which could not be determined. 
The species differs from all more exactly described species of this group 
through the position of the sexual organs, the form of the cystocarps and the 
belt-shaped chromatophore. It may have been observed earlier, however, and pos- 
sibly some of the plants mentioned under the name of Callithamnion minutissimum 
have belonged to this species. ZANARDINT’s species of this name (Synops. Alg. mar. 
Adr. 1841 p.176; Hauck, Oesterr. bot. Zeitschr. 1878 Taf. II fig. 7—8), however, be- 
longs not to this group; and as to Sunr’s species (Kürzına Spec. alg. 1849 p. 640, 
Tab. phye. XI tab. 57), it is impossible to identify it from the description and figures. 
On the other hand, the specimens referred to that species by Crovan (Alg mar. du 
Finistère No. 114, Florule du Finistère p.134) show so much resemblance with the 
species here described, that they might probably be identical. This, however, 
cannot yet be decided with certainty as the specimens of Crovan bear no sexual 
