are located and contiguous to a rear wall of the upper casing member a portion of the upper casing member surrounded by the ribs is reduced in thickness as compared to the remaining portion of the upper casing member application_number US 91413397 A description now a tape cassette according to the present invention will be described hereinafter with reference to fig1 to 4 of the accompanying drawings a tape cassette of the illustrated embodiment is embodied in the form of a digital video cassette dvc the tape cassette includes a casing 3 formed by joining an upper casing member 3a and a lower casing member 3b to each other also it includes a pair of tape reels 2 rotatably received in the casing 3 and a tape 1 wound on the tape reels 2 so as to be stretchedly extended therebetween the casing 3 is formed on both sides of a front surface thereof with a pair of openings 13 which permit an interior of the casing 3 to communicate with an exterior thereof the tape 1 is arranged so as to be reversibly guided from any one of the tape reels 2 through one of the openings 13 to an exterior of the front surface of the casing 3 and then through the other opening 13 to the other reel while being stretched between both tape reels 2 further the tape cassette includes a cover operating mechanism for selectively exposing a portion of the tape 1 guided along the front surface of the casing 3 the cover mechanism includes a front cover 4 for selectively covering a front surface of the portion of the tape 1 guided along the front surface of the casing 3 an upper cover.