Fig. 1
(image in b from Ref. [18] and licensed under CC BY 4.0 (link: https://creativecommons.org/licenses/by/4.0/))
Hydractinia morphology, life history, and culture. a Colony growing on a microscope slide. Major morphological structures are labeled. This colony was explanted from a larger colony. The yellow-brown rectangle at the center is a layer of chitin that is slowly deposited below the mat as the colony grows and indicates the outline of the original explant. Scale bar = 1 mm. b Life cycle of Hydractinia. c Typical setup of a 39-L glass aquarium for culturing Hydractinia