THE PRESIDENT'S ADDRESS. 
203 
in the same way as in our anemophilus phanerogams the pollen 
grains pass as a dust into the air, and are moved to and fro by the 
winds. There are many analogies between Floridese and higher 
phanerogams regarding their sexual conditions. Thus among the 
former we find many species which are diyecious, similar to the 
lowest phanerogams among gymnosperms, and to others of higher 
order. The chances for fertilization in their case are therefore quite 
similar to those applying to duecious phanerogams. Often the 
plants of the two sexes grow at a considerable distance from one 
another. In the spring of 1878 Dr. Dodel-Port, during a series of 
microscopical examinations of the red seaweeds of the Adriatic, 
extending over four weeks, found only female and agamic (tetra- 
sporous) specimens of Polysiphonia sub (data, T. Ag., and looked in 
vain for male specimens, of which at the end only of his investiga- 
tions he could obtain a few. Their respective localities of growth 
were evidently considerably apart, and yet at all times Dr. Dodel- 
Port found specimens of the former in all stages of fertilization. 
The spermatozoids discharged by the male plants therefore found 
their way to the distant female plants in spite of their own immo- 
bility and general passive behaviour. The sea-water must therefore 
have frequently been in rapid motion. 
These facts being ascertained, the thought easily suggested itself 
that possibly animals might take part in the fertilization, particularly 
as there is never a w T ant of small marine animals roaming about in 
the Florideye forests, such as — infusoria, Crustacea, annelids, star- fish, 
and so on. But what particularly attracted Dr. Dodel-Port's atten- 
tion, was the regular occurrence of innumerable bell-shaped animal- 
cules (vorticelke) in the shrub-like branches of Polysiphonia subulata. 
In the course of closer investigations of the phenomena of fertiliza- 
tion, Dr. Dodel-Port eventually arrived at the full conviction that 
in the case of Polysiphonia the little vorticellye facilitate the 
conveyance of the antherozoids to the trichogyne, 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 at 
their fertilization. 
During a long series of investigations of the reproductive phe- 
nomena of Polysiphonia, Dr. Dodel-Port found regularly on the bushy 
thallus, and particularly upon the uppermost and youngest branches, 
an enormous number of vorticellae which had settled there, and were 
as usual in incessant motion. Often they appeared in dozens in 
