ZOOPHYTES 



21 



matter; a power so remarkably developed in those polypes 

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

 like expansions or " pinuac" of the Virgularia is injured, the 

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

 to possess no motion beyond that of the pinna; ; 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" ai-e included. The species most commonly 

 exhibited in museums is the Gorgonia flahdlum, which has 

 occasionally been thrown ashore on difliirent parts of the 

 coast of England and Scotland. As usually seen, the surface 

 consists of a hard calcareous material ; but originally tliis was 

 covered with an irritable living membrane, in the cells of Avhich 

 the polypes lived. If the Sea-fan were formed throughout of 

 a hard, unyielding 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 resembling horn, 

 which bends under the force of streams and cmrents, and is 



Fie. II. — Keu CuitAL. 



