Webster’s Revised Unabridged Dictionary · 1913
Fierasfer
Fi′e·ras′fer (fī′ē·răs′fẽr), n. [NL.] (Zoöl.) A genus of small, slender fishes, remarkable for their habit of living as commensals in other animals. One species inhabits the gill cavity of the pearl oyster near Panama; another lives within an East Indian holothurian.