An apparatus for storing, feeding and measuring a weft yarn of a jet weaving machine is provided with an annular housing containing at least one weft yarn-stopping device. In said stopping device a stop member is arranged for a displacement between a passive position and a stop position. Said stop member is actuated by a current-energizable solenoid coil. Said stopping device is provided with a bistable and self-holding mounting arrangement for the stop member. Said stop member is connected with a polarized permanent magnet. For an actuation of the stop member in order to displace it away from its initial end position said current-energizable solenoid coil is electrically connected with a current-direction-reversing-circuit.