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Calliactis polypus

Hermit Crab Anemone

Tara Gatehouse (2014)




Fact Sheet



Physical Description


Life History & Behaviour



Gas Exchange & Excretion


Anatomy & Physiology

External Morphology

Internal Anatomy & Physiology


Retraction-Deflation Sequence


Evolution & Systematics

Evolution with Hermit Crabs


Biogeographic Distribution

Global Distribution

Local Distribution

Conservation & Threats

References & Links


C. polypus reproduces via both sexual and asexual methods. Asexual reproduction occurs via longitudinal fission, where one anemone splits into two individual anemones over a period of time. (Brooks and Mariscal, 1985) However, it is not known how often C. polypus reproduces asexually, as the most observed form of reproduction is sexual. (Brooks and Mariscal, 1985)


Figure 1: Asexual reproduction of anemone via longitudinal fission. (Bocharova and Kozevich, 2011)

Anemones can be both dioecious and hermaphroditic. Sexual reproduction in anemones relies on the formation of gametes. As anemones have no true gonads, their gametes accumulate on strips of tissue in the mesenteries. (Bocharova and Kozevich, 2011) Gametes then enter the gastrovascular cavity to be emptied through the mouth. Males and females release gametes into the surrounding water, known as spawning. The gametes then meet and are fertilised, either internally or externally, forming a zygote. The zygote develops into a planula larvae that often bears a well developed tuft of sensory cilia at its aboral end (Ruppert, 2004). It was found that C. polypus spawned, fertilised internally, and reared the planula larvae in the gastrovascular cavity for up to 36 days before releasing the planktonic offspring. (Cutress et al., 1970)

'Anemone Spawn' from Coral Morphologic on Vimeo. Sperm being released by Epicystis crucifer.

Due to small anemones being discovered, it is more likely that sexual reproduction occurs the majority of the time between individuals of Calliactis sp. Small anemones suggest that they have recently settled after undergoing metamorphosis from planktonic planula larvae. (Brooks and Mariscal, 1985)