Beard Worms: Pogonophora

The tentacles of the beard worm are extended from their tube opening, but the worms can withdraw quickly into their tubes when threatened by crabs or other predators.

Males and females must mate to reproduce. The males of some species release sperm packets into the water. They eventually settle on or near the tube openings of female worms. The packets break down, and sperm is released. The sperm find their way into the reproductive ducts of the females, and the eggs are fertilized inside their bodies. The eggs apparently develop inside the tube. The larvae (LAR-vee), or early stage of the animal, are free-swimming, but eventually settle into the mud and begin producing their own tubes and acquiring bacteria.