Xxiv.; Webber, The Development of the Antherozoids of Zamia, Bot.
Mycelium present, antheridia with antherozoids, oogonium with single oosphere: Monoblepharidaceae.
Mycelium present; antheridia but no antherozoids; oogonia with one or more oospheres: Peronosporaceae, Saprolegniaceae.
Mycelium poorly developed or absent; oogonia and antheridia (without antherozoids) known in some cases; zoospores common: Chytridiaceae.
Monoblepharis has oogonia with single oospheres and antheridia developing a few amoeboid uniciliate antherozoids; these creep to the opening of the oogonium and then swim in.
The oosphere is in all cases fertilized while still within the oogonium, the antherozoids being admitted by means of a pore.
It much more resembles the antherozoids of Bryophyta and certain Pteridophyta than any known among other algae.
The antheridia, which arise in the conceptacular cavity as special cells of branched filaments, are similarly discharged whole, the antherozoids only escaping when the antheridia are clear of the conceptacle.
The antherozoids are attracted to the oospheres, round each of which they swarm in great numbers.
Until the recent discovery by Williams of motility, by means of a single cilium, of the antherozoids of Dictyota and Taonia, they were believed to be immotile bodies, like the male cells of red seaweeds.
The discovery by Brebner of the specific identity of Haplospora globosa and Scaphospora speciosa marks an important step in the advance of our knowledge of the group. Three kinds of reproductive organs are known: first, sporangia, which each give rise to a single tetra-, or multi-nucleate non-motile, probably asexual spore; second, plurilocular sporangia, which are probably antheridia, generating antherozoids; and third, sporangia, which are probably oogonia, giving rise to single uninucleate non-motile oospheres.
In similar organs on separate plants the much smaller antherozoids arise.
A, antherozoids, b, a female gamete.
Williams, " On the Antherozoids of Dictyota and Taonia," Ann.
I) of the same nature as those of the zoospores and antherozoids of algae, mosses, &c.
(1900); Webber, " Development of the Antherozoids of Zamia," Bot.