Recognising the family
When alive, the body of cirratulids is often red, orange or yellow in colour, as are the branchiae and tentacular filaments which may almost cover the body (however, species of Dodecaceria are dark green or black). Parapodia are absent and the chaetae emerge directly from the body wall. Terebellidae and related families may superficially present in a similar way to cirratulids, as a mass of filaments. However, in terebellids these are either filaments which arise from the mouth, or branchiae, restricted to 2-3 anterior-most segments. Cirratulid branchiae occur throughout the body, one pair per segment.

Distinguishing species
Cirratulidae are a difficult family to identify as palps, branchiae and tentacular filaments can easily become detached although their scars should still be visible. Incomplete specimens (those not having the complete thorax and all abdominal segments) may be difficult or impossible to place in a genus or species, as many characters refer to posterior segments.

The genera of cirratulids are poorly defined; Blake (1996) has recently partially revised the group, recognising 3 groups of genera:

• Multitentaculate genera (eg Cirratulus, Cirriformia)
• Bitentaculate soft-substrate genera (eg Caulleriella, Chaetozone, Tharyx)
• Bitentaculate hard substrate genera (eg Dodecaceria)

Useful characters for separating species of cirratulids are the arrangement and distribution of tentacular filaments and branchiae. The chaetae are all simple, but structure and arrangement of varies between species: knob-tipped hooks or spines, and smooth or serrated capillaries may be present.

Further work is required on the family and Blake (1996) suggests that many species with reportedly global distribution represent will be found to represent species complexes within which some species are presently undescribed.