TILE SALANGANA. 3v9 
long the wonderfully delicate polysiphonias, callithamnias, ploca- 
mias, and delesserias, whose elegant rosy scarlet or purple leaves 
are the amateur’s delight, and when laid out on paper resemble 
the finest tracery, defying the painter’s art to do justice to their 
beauty. It likewise numbers among its genera the chalky coral- 
jines and nullipores, which on account of the hardness of their 
substance were former.y considered to be polyps, but whose 
true nature becomes apparent on examining their internal 
structure. 
The Chondrus crispus, or Carrigeen, which grows in such vast 
quantities on the coasts of the British Isles, also belongs to the 
rhodosperms, though when growing, as it frequently does, in 
shallow tide-pools, exposed to full sunlight, its dark purple colour 
fades into green or even yellowish white. When boiled it 
almost entirely dissolves in the water, and forms on cooling a 
colourless and almost tasteless jelly, which of late years has been 
largely used in medicine as a substitute for Iceland moss. Si- 
milar nutritious gelatines, which also serve for the manufacture 
of strong glues, are yielded by other species of rhodosperms. 
among others by the Gracillaria spinosa of the Indian Ocean, 
which the Salangana (Hirundo esculenta), a bird allied to the 
swallow, is said principally to use for the construction of her 
edible nest. 
The steep sea-walls along the south coast of Java are clothed 
to the very brink with luxuriant woods, and screw-pines strike 
everywhere their roots into their precipitous sides, or look down 
by thousands from the margin of the rock upon the unruly sea 
below. The surf of incalculable years has worn deep caves into 
the chalk cliffs, and here the Salangana builds her nest. Where 
the seais most agitated whole swarms are observed flying about, 
and purposely seeking the thickest wave-foam. From a pro- 
jecting cape, on looking down upon the play of waters, may be 
seen the mouth of the cave of Gua Rongkop, sometimes com- 
pletely hidden under the waves, and then again opening its 
black recesses, into which the swallows vanish, or from which 
they dart forth with the rapidity of lightning. While at some 
distance from the coast the blue ocean sleeps in undisturbed 
repose, it never ceases to fret and foam against the foot of the 
mural rocks, where the most beautiful rainbows glisten in the 
ecernally rising vapours, 
