Remipedia is a class of blind crustaceans found in coastal aquifers which contain saline groundwater, with populations identified in almost every ocean basin so far explored, including in Australia, the Caribbean Sea, and the Atlantic Ocean. The first described remipede was the fossil 'Tesnusocaris goldichi' (Lower Pennsylvanian). Since 1979, at least seventeen living species have been identified in subtropical regions around the world.

Remipedes are 1–4 centimetres (0.4–1.6 in) long and comprise a head and an elongate trunk of up to thirty-two similar body segments. They lack eyes and pigmentation. Biramous swimming appendages are laterally present on each segment, and the animals swim on their backs. They are generally slow-moving. They are the only known venomous crustaceans, and have fangs connected to secretory glands, which inject a combination of digestive enzymes and venom into their prey.

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