92 



L.M.B.C MEMOIRS 



No. V. ALCYONIUM. 



BY 



SYDNEY J. HICKSON, M.A., D.Sc, F.K.S. 



Introduction. 



The Order Alcyonaria is represented in the British seas 

 by very few species ; and as none of these are commonly 

 found between tide marks nor thrown up on the beach by 

 storms, they are very little known to the general public. 

 The Alcyonarian which is best known to the public is 

 the precious coral of commerce, Cor allium rubrum, from 

 the Mediterranean Sea, but other Alcyonarians, such as 

 the Organ pipe coral (Tubipora), the Blue coral 

 (Heliopora), the Sea-fans (Gorgonacea) and the Sea-pens 

 (Pennatulacea) are familiar objects in our Zoological 

 Museums. 



When a living Alcyonarian is examined in sea-water a 

 number of tubular radially symmetrical bodies are seen 

 to project from the surface, each of which is provided at 

 its free extremity with eight pinnate tentacles arranged 

 in a circle round a slit-like mouth. When the water is 

 disturbed, or the Alcyonarian removed from the water, 

 these bodies slowly retract beneath the surface of the 

 coral, until their presence is indicated only by an eight- 

 rayed star-like aperture. These bodies are usually called 



