i 2 6 How to Keep a Salt- Water A quarium. 
spores of the plant worked with by sight, as it is almost impossible 
to avoid getting other red-seaweed spores introduced into the 
aquarium. It is even more important to be able readily to 
distinguish the tetraspores. These germinate as a rule much more 
freely than the sexually produced carpospores. 
When the female plant is well established introduce a male 
plant with antheridia. Spores will readily form, and the fertilization 
can be observed. When the spores appear ripe prepare some 
small o-in. squares of mica and suspend them by silk threads to 
a transverse section of an ordinary bottle-cork. The cork will float 
on the surface of the water and the mica square should be so 
arranged as to hang suspended among the fruits. These mica 
squares will soon have spores fall on them which will attach them¬ 
selves by a foot. It is as well only to allow two or three spores to 
each mica plate. These can be removed at will from the aquarium 
and can be examined under the microscope so that the whole growth 
can be watched and drawn. If other spores of green or brown algae 
settle on these plates they are easily recognised, and can be 
removed with a piece of cotton wool fixed on a match end. 
It is necessary to see that the periwinkles do not climb up the 
seaweed and eat the spores on the mica, but a very little care in 
hanging the mica plate will prevent this. 
The second year of observation is much more interesting than 
the first, as one can watch the development of the antheridia and of 
the young fruits on our two plants, and one has the satisfaction of 
knowing that they are really healthy normal plants with which we 
are dealing, whereas a plant taken from the sea and just kept in 
sea-water without any care, is really degenerating, and observations 
made on it are really observations on a dying plant. 
May , 1902 . 
Rina Scott. 
