Merry Christmas! I thought today's post deserved a Christmas theme, so I will write about the Christmas Tree Worm.
Photo credit: By Nhobgood Nick Hobgood (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)
Christmas tree worms (Spirobranchus giganteus) live in coral reefs worldwide, and live in tubes. Their pretty tree-shape is made of appendages they use to respire and feed on plankton and suspended food particles. Disturbances cause them to retreat into their tubes, which they attach to coral. The worms, like many other marine invertebrates, breed by releasing sperm and eggs into the surrounding seawater. Fertilized eggs will develop into larvae, which then form their burrows on coral.
http://marinebio.org/species.asp?id=543
http://marinebio.org/species.asp?id=543