XIV. ] ALGZ. 201 
Fucus. C shows the position of the Conceptacles, 
which contain Sporangia, and P denotes the pores or 
openings of the Conceptacles. In fig. 150 one of 
these conceptacles is enlarged. 
O is the external orifice (P in 
fis. 149), P the perispores or 
sporangia. In some species the 
Antheridia are contained within 
the same conceptacle as the 
perispores; in others they are 
contained in separate concep- 
tacles on the same or other plants. They consist of 
ovoid sacs containing two Sfermatogzoids with cilia. 
When set free they enter the conceptacle by its 
external orifice or pore, attach themselves to a 
perisporeé, penetrate one of the spores contained 
therein, and by thus mingling their protoplasms, 
fertilisation of the spore is effected. 
Algologists divide this group of plants into five 
subdivisions, as follows :— 
I. Olive-coloured seaweeds (J/elanosperme@). 
2. Rose-coloured seaweeds (Rhodospermee@). 
3. Green-coloured seaweeds (Chlorospermea). 
4. Brittleworts (Dzatomacee),. 
5. Volvoces ( Volvocinee). 
The first of these (Velanospermee) comprises the 
various species of Fucus and Laminaria so plentiful 
on all our coasts, Every visitor to the seaside must 
be familiar with several species of Fucus, long lines 
of which are left by the receding tide. Who has 
not turned over quantities of this leathery jetsam to 
find the tiny crabs which seek shelter beneath it, 
Fic. 150.—Conceptacle. 
