THE SALANGANA. 399 



long the wonderfully delicate polysiphonias, callithamniae, ploca- 

 mias, and delesserias, whose elegant rosy scarlet or purple leaves 

 are the amateur's delight, and when laid out on paper resemhle 

 the finest tracery, defying the painter's art to do justice to their 

 beauty. It likewise numbers among its genera the chalky coral- 

 lines and nullipores, which on account of the hardness of their 

 substance were formeny considered to be polyps, but whose 

 true nature becomes apparent on examining their internal 

 structure. 



The Chond/rus 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 tl|e Qracillaria spvnosa of the Indian Ocean, 

 which the Salangana {Hwwado 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 sea is 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 Grua Eongkop, 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 

 eternally rising vapours. 



