Bamboo-worms

Bamboo-worms (Family Maldanidae) are tube-building worms, whose bodies have long segments separated by nodes or joints, reminiscent of a bamboo plant. Each species usually has a fixed maximum number of segments and if part of its body is removed, the worm can regenerate the exact number of segments lost. Amazingly, bamboo-worms can regenerate the anterior or posterior ends—or both simultaneously. However, if the critical mid-body segments (usually 8 to 10) are lost, it proves fatal.