Ceriantharia
order of cnidarians
The tube-dwelling anemones (Ceriantharia) are a subclass of the Anthozoa. They resemble sea anemones. Sea anemones have a base plate, tube-dwelling anemones do not.
![](http://up.wiki.x.io/wikipedia/commons/thumb/9/91/Mittelmeer-Zylinderrose_%28Ceriantharia_membranacea%29_1.jpg/505px-Mittelmeer-Zylinderrose_%28Ceriantharia_membranacea%29_1.jpg)
Most tube-dwelling anemones reproduce sexually. About 100 species have been described; most live in a depth of less than 50 metres (160 ft). Unlike sea anemones, tube-dwelling anemones live in soft sediments. The name "tube-dwelling anemone" comes from the fact that these animals build a tube out of the sandy sediments. In the case of danger, they retract into the tube.