Common Brittle-star
Ophiothrix fragilis
Disc diameter up to 15mm

Often found at low tide among seaweeds and under stones, especially where silt and sediment collect. Body comprises a central, flattened disc and five, narrow and radiating arms; the surfaces of both disc and arms are rather spiny. Colour rather variable but usually purplish brown but with paler bands visible along arms. As its name suggests, legs are brittle and easily broken. Widespread.