Figure 2.

This photograph shows the bright blue acrorhagi used in intraspecific combat [20] and red tentacles used in prey capture and defence against predators of the Australian sea anemone, Actinia tenebrosa. Both structures have a high density of nematocysts, but they have different nematocysts complements (for example, holotrichs are abundant in acrorhagi and basitrichs in tentacles). Photo credit: Chloe van der Burg.