composed of dense whorls of exceedingly minute, glassy filaments, frequently - 
occupy the place of tetraspores in the involucres. Colour, a fine trans- 
parent crimson, instantly discharged, with a crackling noise, in fresh water. 
Substance rather rigid and crisp, becoming flaccid after exposure to the air. 
In drying the plant adheres, but not very closely, to paper. 
A long known and beautiful plant, found on all the British 
shores, and widely dispersed through the ocean ; being found not 
only in the Atlantic, but in several parts of the Southern Pacific 
Ocean. From Van Dieman’s Land I have seen very numerous” 
specimens undistinguishable from British-grown ones. 
When quite eae it is remarkably crisp and firm in eae 
the points of its filaments standing firmly out, when the tuft is” 
removed from the water. But it very rapidly becomes flaccid, 
and if dropped into’ fresh water, the membranous walls of its 
filaments burst asunder with violence, and with a sharp crackling” 
noise, discharging the contents of the cells into the water. These 
form a fine powder of a brilliant carmine colour, and might, no 
doubt, be used as a pigment if the plant could be collected in 
sufficient quantity. Paper stained with this powder retains its 
brilliancy of colour in the Herbarium for many years. These 
remarks apply equally to other species of the genus. 
I may add that, delicate as the structure of this plant assuredly 
is, ho marine Alga is more patient of confinement, or may be 
more easily domesticated. A tuft placed in a closed bottle of 
sea water in April 1846, is now, after more than two years’ im- 
prisonment, apparently as fresh and healthy as when first taken 
from the sea. ‘The water has not been changed, and is perfectly 
clear and pure. The plant has not grown much, as the bottle 
is a small one, but its threads reach nearly to the surface of the 
water; and no decay has taken place. 
: 
Fig. 1. GrIFFITHSIA SETACEA; tuft :—of the natural size. 2. Upper part ofa 
fertile branch. 3. Involucre with ¢etraspores. 4. Ramulus from the same. 
5. A tetraspore. 6. Involucre with favelle. 7. Ramulus from the same :— 
all more or less highly magnified. 
