Worm snails

On coral reefs and beneath dock pilings lurks a mollusk masquerading as a worm: the worm snail family Siliquariidae. At first glance, one might mistake their shells for twining tubes of a polychaete worm or serpentine coral. Unlike their coiled snail cousins, worm snails grow irregular, tube-like shells cemented to hard surfaces, often with a slit or series of holes along the tube’s length. These sessile gastropods have abandoned mobility – once they settle as larvae, they fuse in place and never budge again. Instead of roaming for food, a worm snail casts out a mucus net into the water to trap plankton and detritus, then reels the net back in to consume whatever sticks