Wheel Wearers: Cycliophora

Wheel wearers are microscopic animals that live in the mouths of Norway lobsters. Symbion pandora is the only fully described species. Scientists have found two other species, but do not have enough details to describe them thoroughly.

The main phase in the life cycle of wheel wearers is the feeding stage. Wheel wearers in this stage are about 0.01 inch (350 micrometers) long. The body is made up of a bell-shaped mouth funnel, a trunk, and a stalk with an attachment disk. The rim of the funnel is made up of hairlike fibers alternating with muscle cells. The fibers are used to collect food, and the muscle cells close the mouth when the animal stops feeding. The inside of the funnel is covered with hairlike fibers. The funnel connects to the trunk with a narrow, movable neck. The trunk is slightly egg shaped and contains a U-shaped digestive system that runs from the mouth through the stomach to the anus, which is close to the neck. The trunk narrows to a stalk that leads to the attachment disk.