A tape cassette comprises a housing and a pair of reels mounted for rotation in the housing. A recording tape is wound on the reels and extends therebetween for transport from one of the reels to the other. The housing is formed with an opening through which a transducer can gain access to the recording tape for recording or reproducing signals on or from the recording tape. Front and back lids are connected to the housing and movable between a closed position wherein the front and back lids block the opening and form a channel capable of enclosing the recording medium at a front portion of the housing and an open position wherein the front and back lids are displaced from the opening and from the recording medium. The back lid is formed to leave a pair of gaps near either end thereof capable of accommodating passage of the recording medium therethrough when the front and back lids are in the closed position. When the front and back lids are in the open position, a transducer can be introduced into or withdrawn from the housing. When the transducer is introduced into the housing, the tape is wrapped around the transducer and the front and back lids can be closed, with the tape passing unhindered through the gaps at the ends of the back lid.