The ophtalmocerids are an order of polizoans belonging to Terribilivermia. Its anatomy is very similar to the rest of terribilivermian worms; each of its appendices has a small mouth and a gastrovascular cavity where they digest food, in addition to serving as legs. What is truly unique about this group is its "double protective shell" and its evolutionary origin. This aragonite shell is located at each end of these organisms and provides protection against predators, retracting its soft body between them. These shells evolved from the compound eyes of the terribilivermians. In fact, tens of thousands of tiny lenses fused together can be observed under a microscope, forming the shell structure. Obviously, this adaptation has made them lose the vision present in other terrribilivermians, but in return has given them much-needed protection to survive on the dangerous reefs of Polinices.
The image shows the species Bicochlea striata, which is 5 cm long.