FERTILISATION OF RED SEA-WEEDS BY ANIMALCULA. 395 
must have found their way to the distant female plants in 
spite of their own immobility and general passive condition. 
The sea-water, therefore, must have been frequently in vivid 
motion. 
These facts being ascertained, the idea readily suggested 
itself that possibly animals might take part in the fertilisation, 
particularly as there is no lack of small marine animals roaming 
about in the Floride@ forests, such as Infusoria, Crustacea, 
Annelids, Starfish, Bryozox, Sponges, &c. But what particularly 
attracted Dr. Dodel-Port’s attention was the regular occurrence 
of innumerable bell-shaped animalcules (Vorticella) on the shrub- 
like branches of Polysiphonia subulata. On closer investigation 
of the phenomena of fertilisation in the female organ, during 
and after adhesion of the antherozoid with the trichogynium, 
Dr. Dodel-Port eventually arrived at the conviction that in the 
case of Polysiphonia the little Vorticelle facilitate the conveyance 
of the antherozoids to the trichogynium, and that they act 
according to a natural law, in the same way as do the pollen- 
collecting bees when, by visiting the willow-catkins, they assist 
in their fertilisation. The investigation of the sexual conditions 
of Floridee is as yet in its infancy; it is to be hoped that more 
numerous researches in this direction will shortly be made, and 
possibly relations may be found to exist between other species 
of this order and certain animals similar to those discovered 
by Dr. Dodel-Port in the case of Polysiphonia and Vorticella. 
The details of the interesting relations in this case are briefly 
as follows :— 
Fig. 1 represents the male reproductive organ (antheridium) 
of Polysiphonia subulata, magnified 480 times. These antheridia 
often appear in large numbers at the upper branch-ends of the 
male plant, laterally close to the apex which continues its growth, 
at the spot where in the vegetative state young branches would 
form. In their earliest stage the antheridia consist, like the 
young branches, of a single row of cells. By repeated longitudinal 
and lateral divisions a polycellular body is soon formed, which 
begins with a short stem-cell (st), and which on the side furthest 
away from the maternal thallus-branch is protected by a forked 
hair (gh). The ripe antheridium in external appearance reminds 
one very much of a maize-cone; a row of four to six cylindrical 
cells (aa) in the axis of the whole organ represents the spine of 
