88 
OUR MARINE ALG.E. 
The antlieridia are reproductive organs very imperfectly 
understood. Dr. Harvey describes them thus:—“ The an- 
theridia are oval, somewhat pointed at one end, and contain 
a reddish orange granule, and they are furnished with two 
extremely vibratile hairs or cilia, one of which issues from 
the narrow extremity of the corpuscle; the other, which is of 
greater length, from the coloured granule. The corpuscles 
escape from the antheridium into the surrounding water, 
where they perform rapid circular movements like the 
zoospores of the green series of Fresli-water Algas, the narrow 
end of the corpuscle being in front, and the cilium rising 
from the coloured granule trailing behind.” 
In regard to the reproductive agency of the zoospores, 
the following description may be given. The cells at first are 
filled with endochrome nearly homogeneous and fluid; this 
becomes more granulated, the granules adhering to the inner 
surface of the wall; they then detach themselves and float 
freely in the cell, at first irregular in shape, then spheroidal. 
Afterwards they congregate into a dense mass in the centre 
of the cell, when one by one the granules, becoming detached, 
move vivaciously in the centre of the cell, push against the 
sides of the cell-wall till they pierce it, then escape into the 
surrounding water, continuing their movements until they 
become fixed to some submerged object, where they develop 
cells that grow into algaB, similar to those from whose cells 
they issued. 
Thus, m review, we have the root and frond with their 
various characteristics, the cellular structure, and the organs of 
reproduction, as criteria by which our Marine Algae are 
classified and arranged There are three sub-orders ; first— 
the Bliodospermeae, which are distinguished by the red colour 
of their spores, and their red or brown fronds; second—the 
Melanospermeae, distinguished by their olive-green spores and 
similarly coloured fronds, turning almost black when dried; 
and thirdly we have the sub-order of Clilorospermeae, known 
by their sea-green spores and fronds, except in several species 
where they are purple. All the series are divided into 
families, genera, and species, these being determined by the 
fructification, cellular tissue, form and colour of the frond. 
All our Marine Algae are included under three sub-orders, 
25 families, 122 genera, and 876 species. But many of 
the species are exceedingly variable, none more so than the 
Chondrus crlspus, needing very careful microscopic examina¬ 
tion to discriminate them. 
Attempts have been made by botanists to classify our sea¬ 
weeds according to definite zones of growth, and so we hear 
