Umbellula

Umbellula is a genus of deep-sea cnidarians in the monotypic family Umbellulidae. Sea pens of this genus are known to be bioluminescent and hermaphroditic.

==Description== Species of Umbellula form colonial structures, which is common amongst pennatulacean octocorals (sea pens). Around the primary polyp distal region, secondary polyps form which are either larger autozooids (feeding polyps) or smaller siphonozooids (water circulation polyps). The morphological adaptations of Umbellula species reflect adaptations to unique deep-sea environments, including differences in polyp arrangement and sclerite presence or absence. Species such as Umbellula encrinus having a typical cluster of autozooids, while Umbellula pomona only possessing a terminal cluster of three autozooids. Umbellula autozooids are found clustered at the very end of their stalk, unlike most other sea pens in which autozooids are spread along the rachis.