OOSPOREM. 
283 
tacles. The oospheres are expelled, surrounded by an inner membrane of the oogonium, 
and escape through the opening of the conceptacle ; the antheridia at the same time 
become detached, and collect in numbers before the mouth of the conceptacle when the 
fertile branches are lying out of the water in moist air. When they again come into 
contact with the sea-water, the antheridia open and allow the antherozoids to escape, 
the oospheres at the same time escaping from the envelope which still surrounds them, and 
which is then seen to consist of two separated layers (Fig. 185, II). The antherozoids 
collect in numbers around the oospheres, become firmly attached to them, and when 
their number is sufficiently great, their movement becomes so energetic that they impart 
to the very large oosphere a rotatory motion which lasts for about half an hour. 
Whether the antherozoids force themselves into the oosphere Thuret leaves undecided ; 
but analogy with the processes observed by Pringsheim in Faucheria and CEdogonium 
scarcely admits of a doubt that one or several of them mingle their substance with that 
of the naked ball of protoplasm. A short time after these processes are completed, the 
fertilised oosphere surrounds itself with a cell-wall, fixes itself to some body or other, 
and begins, without any period of rest, to germinate, and, lengthening at the same time, 
Fig. \Z<~,.—Fttciis i'esiculos2{s (after Thuret); A a branched hair bearing antheridia; 5 antherozoids ; / an oogonium, 
after the contents have divided into eight portions (oospheres), surrounded by simple hairs (/) ; // commencement of 
the escape of the oosphere ; the membrane (a) has burst ; the inner membrane i is ready to open (the two together 
constitute an inner layer of the cell-wall of the oogonium) ; /// oosphere surrounded by antherozoids ; IV, V, germination of 
the oospore (B x 330, all the rest x 160). 
undergoes first of all a transverse division followed by numerous other divisions. The 
mass of tissue thus formed puts out from the part on which it rests a root-like hyaline 
organ of attachment, while the thick free end forms the growing apex (Fig. 185, IV). 
There are numerous marine Algae, included in the group of Phaeosporeae, which 
resemble the Fucaceae as well in the structure of their vegetative organs as in the 
presence of a colouring-matter mingled with their chlorophyll. To this group belong 
the often enormous Laminarieae (Macrocyjtis, Laminaria, Lessonia, etc.), as also the 
smaller Ectocarpeae, Sphacelarieae, Chordarieae, and Dictyoteae. 
The Phaeosporeae are reproduced non-sexually by zoogonidia, a mode of reproduc- 
tion which does not occur among the Fucaceae. In some, bodies which appear to be 
antheridia have been detected, but no oogonia ^ 
^ [Goebel has observed (Bot. Zeitg. 1878) the conjugation of zoogonidia in two species of 
Ectocarptis : see also Berthold, in Mittheil. d. Zool. Stat. Neapel, II, 1881.] 
