Tube Anemone Larva

Tube anemones, order Ceriantharia, are members of the class Anthozoa, along with the corals. Cerianthids are solitary, tube-dwelling anemones. They live mostly buried in the sand in tubes which they secrete, composed of fired nematocysts and sand particles. When disturbed the anemone rapidly retracts its oral tentacles into the safety of its tube.

Cerianthids have planktonic larvae that may live for six months in the water column before settling to the sea floor. The fertilized anthozoan zygote undergoes cleavage and gastrulation to produce a ciliated planula, the common planktonic larva. This larva is highly predatory and amongst the largest of the ciliated larvae. Internally it is ciliated too and when it feeds on a larval shrimp (see above), it is possible to watch the bits of shrimp floating around inside! It drifts through life like a communications satellite, inhabiting the surface waters and is commonly collected in surface plankton tows.

Click here to view the 'Picture of the Week' archive.