sand flea

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of various small crustaceans living on sandy beaches.
2. n. See chigoe.

Century Dictionary and Cyclopedia

1. n. The chigoe or jigger, Sarcopsylla penetrans.
2. n. A sand-hopper or beach-flea; one of numerous small amphipod crustaceans which hop like fleas on the seashore. A common British species to which the name applies is Talitrus locusta. See beach-flea, and cuts under Amphipoda and Orchestia.

Wiktionary

1. n. Any of various small crustaceans of the order Amphipoda, that are found on beaches and jump like a flea.
2. n. A small tropical flea, Tunga penetrans; a chigoe.

GNU Webster's 1913

1. n. (Zoöl.) Any leaping amphipod crustacean; a beach flea, or orchestian. See Beach flea, under Beach.

WordNet 3.0

1. n. small amphipod crustaceans that hop like fleas; common on ocean beaches