168 THE OCEAN WORLD. 



is quite a colony in itself; placed in pure sea water, it very soon pre- 

 sents certain yellow or grass-like points, which gradually expand and 

 display themselves in their native transparent and animated coralline. 

 Each of these polyps have eight dentate petals, in the centre of 

 which is the mouth ; the body of the polyp is tubular, varying exter- 

 nally in length, traversed internally throughout its entire mass by a 

 tissue studded with reddish spiculae, and furrowed with small reed-like 

 ribbons, common to all the individuals of the association. 



Among the Tiibiporidse may be noted Tubipora musica (Linnaeus), 

 from the Indian Ocean, characterised by its stony tubes, simple, 

 numerous, straight or flexible, parallel, and slightly radiating, of a fine 

 purple, and united together at intervals by transverse bands, so as to 

 resemble the pipes of an organ. The polyp is a brilliant grass green, 

 according to Peron ; the tentacula furnished on each side with two or 

 three rows of granulous fleshy papillae, to the number of sixty to 

 eighty (Lesson). 



The Gorgonia is studded with calcareous or siliceous spiculas which 

 form a crust in drying. This crust is friable, and frequently preserves 

 the colours more or less brilliant which characterise it. Their cells 

 are sometimes hollowed out of the plain surface ; sometimes they occur 

 in the projecting mammals ; these are smooth, rough, or scaly some- 

 times pendent the one from the other. 



These animals attach themselves to solid bodies, sometimes even to 

 each other, grafting themselves or interlacing each other in all 

 directions. In colour they are whitish, pure white, yellow, and apple- 

 green; their shades, passing from olive-brown to deep blue, from 

 vermilion to violet, and from pale yellow to pearly-grey. Each tube 

 or cell contains an individual. The cells are more or less deep, accord- 

 ing to the species. The polyps are composed generally of a hidden 

 portion more or less tubular, and of a star-like portion more or less 

 displayed. This latter portion presents from eight to twelve soft and 

 granulous wattles, susceptible of expansion, like the petals of a flower. 

 When these appendages are displayed, they often attain twice the 

 height of the body ; in this state they are nearly transparent, except 

 towards the extremity. They extend or compress these wattles, dilate 

 or contract the mouth according to their wants ; but their digestive 

 tube is firmly soldered to the cell, while the axis which supports the 

 cells is motionless. What a singular combination is here presented ! 



