CLASS-BOOK OF ZOOLOGY. 161 



§ 687. Tha bodies of Sea-polypes are fastened to the 

 stem and branches of Corals, which are full of minute 

 cells. From these they stretch out their limbs and bodies, 

 presenting in many cases a variety of colors, and causing 

 the bottom of the sea, in some places, to resemble a 

 meadow covered with the most splendid flowers. 



§ 688. The Red Coral (Isis nobilis) is about one foot 

 long, as thick as a finger, and inhabited by milk-white 

 Polypes, not longer than a line. It is found at the bottom 

 of the sea, from 12 to 120 feet deep, and obtained with 

 great difficulty by means of a net, stretched on two poles, 

 each about eighteen feet long, and which cross each other. 



\ 689. They are collected principally on the shores of 

 the Mediterranean, and manufactured at Marseilles into 

 various works of art, such as rosaries, cane-tops, knife- 

 handles, necklaces, etc., which in the East Indies, but 

 more especially in China and Japan, are held in nearly as 

 high estimation as precious stones. 



§ 690. The Horn-corals (Gorgonia) consist mostly of 

 a brown or black horn-like stem, covered with a calca- 

 reous red or yellow crust, on which are found numerous 

 wart-like cells, inhabited by polypes. 



\ 691. The stem of the Horn-coral resembles, at the 

 lower extremity, a broad lobated foot, fastened to the 

 ground. Its upper part, in some species, contains twin- 

 like branches, resembling a broom, and which in some 

 other species, are flat and united like network. The 

 first are called Sea-brooms, the latter, Sea-fans. 



\ 692. The Gorgonias, which are from one to twelve 

 feet high, are found near the sea-shore, chiefly in the 

 tropics, though they are met with north and south of that 

 region. The observer is much amused by their inces- 

 sant motion ; for as they are rendered elastic by the 

 horny substance of which they are composed, they are 

 kept continually swaying by the waves of the sea ; so 

 that, to the eye of the beholder, the Sea-broom is appa- 

 rently sweeping, while the Sea-fan is engaged in fanning 

 the surface of the water. 



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