196 NEMATOPHYCEZ. 
Reproduction takes place by means of asexual zoogonidia, and sexu- 
ally produced oospores. The latter do notat once produce new plants, 
but several zoospores. The zoospores, which are developed in the early 
part of the year from resting-spores of the previous year, produce only 
asexual plants which only form zoogonidia. After a series of asexual 
generations, of variable length, a sexual generation arises, which accord- 
ing to the species is moncecious or dicecious. Fertilization produces 
one oospore in the oogonium, which developes into a reproductive body, 
from the cells of which zoospores proceed in the next period of vegeta- 
tion. Zoogonidia may originate in all the vegetative cells of the Coleo- 
cheetez, and are always formed from the entire contents of the mother- 
cell, escaping through a round hole in the cell wall. 
“In C. pulvinata the terminal cell of a branch swells up, and at the 
same time elongates into a narrow sac, which then opens, and exudes a 
colourless mucilage. The protoplasm of the swollen part, which con- 
tains chlorophyll, forms the oospore, in which a nucleus is visible. The 
antheridia are formed at the same time in adjoining cells, two or three 
protuberances growing out, which become separated by septa; each of 
the cells thus formed, which have somewhat the shape of a flask, is an 
antheridium ; its entire contents form an antherozoid of oval shape 
with 2 cilia, which is endowed with motion like a zoogonidium; its 
entrance into the oogonium has not yet been observed. The effect of a 
fertilization is seen in that the contents of the carpogonium become 
surrounded with a proper membrane and form the oospore.” 
Coleochzte soluta. Prings. Jahrb. t. 1, f. 2. 
Threads radiating from a common centre, furcately branched, 
of equal length, closely packed side by side, prostrate, but not 
connate, forming an orbicular disc. Cells one and a-half to 
three times as long as broad, oogonia placed before the terminal 
cells, globose, corticate. 
Size. Cells :025 mm. 
Rabh. Alg. Eur. iii, 889. Kirch, Alg. Schles. p. 50. 
Attached to aquatic plants. 
Plate LXXVIII. fig.3. Plant of Coleochete soluta X 400. a, Oogo- 
ninm X 250 diam. 
Coleochete scutata. Brdb. Ann. Sci. Nat., 1844, p. 29, t. 2. 
Filaments and their branches radiating from the centre, very 
densely connate in one stratum, forming a kind of parenchy- 
matous orbicular disc ; cells quadrangular, nearly equal or twice 
as long, oogonia subglobose, peripherical, corticate above, naked 
below. 
Sizz, Cells -02--022 mm. 
Rabh. Alg. Eur. iii., 390. Hass. Alg. 217, t. 77, f. 6. 
Prings. Jahrb. t.i., f.4; t iii, f. 8, 4. ; 
Phyllactidium setigerum, Kutz. Tab. Phye. iv. 
On aquatic plants. 
Plate LXXIX. Coleochete scutata. a, plant X 200. 6, portion with 
oogonia. v, portion with antheridia cells. d, zoospore, active and ‘at 
rest. e, development of young plants. 
