sea pen(redirected from Octacorallia)
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Any of various corals of the order Pennatulacea, having a flexible skeleton in the form of a long central shaft with numerous branches on each side.
[From its resemblance to a quill pen.]
(Animals) any of various anthozoan coelenterates of the genus Pennatula and related genera, forming fleshy feather-like colonies in warm seas: order Pennatulacea
any soft coral of the order Pennataluceae, forming feather-shaped colonies.