What does "virgularian" mean?

Virgularian: Any one of numerous species of long, slender Alcyonaria belonging to Virgularia and allied genera of the family Virgularidæ. 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.