12 
The cell-contents are composed, not of one but usually of four green 
cell-membrane is hyaline ter the contents of the spore have 
emerged, there remains ind the outer membrane enclosing the 
inner one ter the four cells have remained some time enclosed in 
ownwa 8 appearance is like that of an ordinary zoospore, and, 
like it, possesses an oval form and a lighter apex, furnished with cilia, 
which he motion is always directed forwards. After a time 
€ movements become faint, and finally cease. The cilia disappear, 
and the light end becomes elongated into a root, ich mes 
comes an organ of attachment, quite like that produced in the 
germination of the zoospores. The rounded the germinating 
: rof. Moebius says :—“ This genus was Miuidastly represented in 
the collection; but comparatively only a few species could be 
od eee terminations, such as measu: ber 
| = SA. consequent i lowi ecies 
more or less certainty.” quently mention the following sp 
bf excisum, Wittr. et Lund. Cooke's British Freshwater Alg@, 
ov: Plate LIX., Fig. 4 Oogonia single, biconically-oblong, mea? 
part of the filament cury 
we song i Cogonia, ‘013-015 x ‘018-025 mm. ; oospore, “09 
5-018 mm. ; sperm-cell, 008-0085 x ‘006-'007 mm.—Cooke, |.¢._ 
f. Moebius gives the following note :—‘‘ Monecious, — 
Prof. 
capable of being recognised by the deep constrictions whic 
round the oogonium, It has a transverse diameter from about 18 #4 and | 
TO eee ee ae te ee ie OE RT, ee ee ey ee ee en ee ee ee a ee oes 2 eet 
