Photo copyright Tim Nicholson.
Whip coral, taken on Horagali Faru (Raa Atoll) Maldives
Whip corals consist of long, cylindrical filaments about the diameter of drinking straws. They are flexible to allow bending in currents. Members of the Octocorallia class they always have 8 tentacles which are pinnate - that is, they possess side branches like a feather.
Atlas of the Maldives: A Reference for Travellers, Divers and Sailors, by Tim Godfrey,(2007)
The Underwater Photographer: Digital and Traditional Techniques by Martin Edge, Paperback, 536 pages (2009)