Coralliomyzon tenens, gen. n., sp. n., associated with the coral Turbinaria peltata gen. n., sp. n., associated with the coral (Esper) in Madagascar, is placed in a new siphonostomatoid family, the Coralliomyzontidae, along with Cholomyzon Stock & Humes, 1969. The new family, close to the Asterocheridae, is characterized chiefly by the maxilliped having 2 basal segments and 2 distal segments forming together a clawlike part, the absence of an inner seta on the first and second segments of the exopod of leg 1, leg 4 reduced to a minute process with 1 or 2 setae, and leg 5 reduced to 2 setae.