Any one of numerous species of long, slender
   Alcyonaria belonging to Virgularia and allied genera of the family
   Virgularidae. These corals are allied to the sea-pens, but have a long
   rodlike rhachis inclosing a slender, round or square, calcareous axis.
   The polyps are arranged in transverse rows or clusters along each side
   of the rhachis.