ZOOPHYTES. 



21 



which are the builders of the coral reefs. If one of the wing- 

 like expansions or "pinnae" of the Virgulariais injured, the 

 rest shrink as if all were hurt. The creature seems, however, 

 to possess no motion beyond that of the pinnae; nor, if put 

 into a glass of water, does it change its position. 



To the same order belongs the group under which the 

 " Sea-fans" are in- 

 cluded. The species 

 most commonly exhi- 

 bited in museums is 

 the Gorgonia flabel- 

 lum, which has occa- 

 sionally been thrown 

 ashore on different 

 parts of the coast of 

 England and Scot- 

 land. As usually 

 seen, the surface con- 

 sists of a hard calca- 

 reous material ; but 

 originally this was 

 covered with an irri- 

 table living mem- 

 brane," in the cells 

 of which the polypes 

 lived. If the Sea-fan 

 were formed through- 

 out of a hard, un- 

 yielding substance, it 

 must be broken to 

 pieces by the waves; this danger is obviated by the central 

 axis being composed of concrete albumen, a substance resem- 

 bling horn, which bends under the force of streams and 

 currents, and is thus preserved. An American poet has 

 referred to this with equal beauty and accuracy: 



" There, with a light and easy motion, 



The Fan-coral sweeps through the clear deep sea ; 

 And the yellow and scarlet tufts of ocean 

 Are bending like corn on the upland lea." 



In another species (Isis hippuris) may be observed an 

 example of the varied but equally effective means by which 

 the same security is attained. Here the stem is composed in 



Fig. 11. RED CORAL. 



