242 RADIATES: POLYPS. 



of the Southern States and of South America, looks 

 like a broad leaf attached to its leaf-stalk ; and when 

 the purple disk is covered with the expanded polyps, as 

 seen in the cut, it is a very beautiful object. The exact 

 form of the separate polyps is shown in Figure 488. 



The Gorgonias abound in tropical seas, but some 

 kinds are also found in temperate regions. The forms 

 are exceedingly various, Figures 489-494, and many 

 of them are very delicate and beautiful, often bearing 

 a very close resemblance to plants ; in all, however, the 

 polyps are short, and secrete a solid central axis of 

 coral. This axis is plainly shown in Figures 491 and 

 493. One of the most common and striking forms of 

 the Gorgonias is the Sea-Fans, which are more or less 

 broad and fan-shaped, the branches in many cases run- 

 ning together so as to form a network, Figure 490. 

 One form of the Gorgonias, the Primnoa, Figure 493, 

 is found even as far north as St. George's Banks and 

 the Bay of Fundy. But the one which has the great- 

 est popular interest is the Red Coral, Corallium rubrum. 

 It is obtained mainly in the Mediterranean. The coral 

 fishers go out in boats, and are provided with a large 

 wooden cross, which is loaded with stone in the centre, 

 and has hempen nets attached to each of its arms. 

 While one man is constantly raising and letting fall 

 this machine upon the coral beds, others row the boat 

 so that the branches broken off are caught up by the 

 nets. From time to time the cross and nets are raised, 

 and the branches of coral which have been entangled 

 in the meshes are secured. 



Closely related to the Gorgonias are the Alcyonacea, 

 of which the Organ-pipe Coral, Figure 494, is one of 

 the most interesting examples. It is of a beautiful 



