Two 9.5x12" animation sheets have lead pencil image area w/figure of Mickey Mouse shown from the waist up w/arms fully extended and mallets in air. Attributed to Ub Iwerks. First image measures 3.25x3-3/8" long w/number "190" in corner. Second image measures 3x5" w/number "333" in corner. Both are from scene six minutes into the cartoon where Mickey uses mallets to play bull's teeth like a musical instrument. Sheets are both lightly aged, w/second sheet having some lt. handling wear along top margin. Image areas remain clean and Exc. Nice images from sequence. Released on Nov. 18, 1928, "Steamboat Willie" was the third of Mickey Mouse's cartoons to be produced, but was the first to be distributed and the first to be shown. It is historically recognized as the first cartoon to feature a fully post-produced soundtrack. Clean and tight historical drawings.