Elytra

Polychaetes like the family Aphroditidae , Polynoidea and Palmyridae can be easily identified based on the scales that are found on their bodies.

Commonly known as "scale worms", these errant polychaetes have modified their cirri into platelike scales or "elytra" which are carried by short stalks on the dorsal side of the body. The elytra bear a variety of sensory structures. They may even function as a protective channel for the ventilating current as most of the scale worms live in tight quarters.