RADACK AND OTHER ISLANDS. 14S 



wherever the waves beat, and under favourable 

 circumstances, assumes a stalactitical form. The 

 colour and silky lustre, which disappear in the air, 

 immediately decided us to ascribe to this substance 

 an animal nature, and the treatment of the bleaclied 

 skeleton, with diluted nitric acid, confirmed our 

 opinion, which had been founded on analogy. 

 The cursory view distinguishes, only by the 

 colouring, and a certain velvet-like appearance, 

 the lythophytes, with fine pores in a living state, 

 from their dead bleached skeletons. We found 

 only the Millepora cceruleay and the Tuhipora 

 musicuy and a yellowish, red-brown Disticho- 

 pora^ with coloured skeletons ; but never saw 

 the latter alive. The kinds with larger stars, or 

 LameUce, have larger and more distinguishable 

 polypuses. Thus an animal, resembling the Acti- 

 nia^ covers the end-branches of a species of Cary- 

 ophylUa, which we also found alive above low 

 water-mark ; the bmnches and roots seem to be 

 bleached and dead. We often see in the lytho- 

 phytes living branches, or parts existing with 

 others that are dead ; and the species, which other- 

 wise assume a spherical form, spread out in places 

 where sand is carried, into flat surfaces, with a 

 raised edge, because the sand kills the upper part, 

 and they can only live and grow on the circum- 

 ference. The enormous masses of one growth, 

 which are met with here and there on the islands, 

 or on the reefs, as rolled pieces of rock, have been 



