Photograph by Peter Parks

The scaleworms (family Polynoidae) are segmented, marine, polychaete worms and are quite closely related to sea mice (family Aphroditidae) and used to be included in the same family. They differ, however, in having no felt over the back, so that the pairs of scales are revealed. The scales are rounded, often overlap and may extend from one end of the body to the other, or from the head backwards for only part of the total length. Their bodies are somewhat flattened and this fits them for their life under boulders and in rock crevices. Many species are quite common, and may be found clinging to the underside of upturned, large boulders or stones on rocky shores. Some live in the burrows of other invertebrates, including those of other worms - or even in the mantle cavity of molluscs, for example limpets.

This image depicts the planktonic larval stage of a scaleworm, although it is missing most of its scales, it is very much alive and kicking! Its buccal mass and gut show it to be a predator used to digesting copepods.

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