Gubelin Swiss turtle mystery clock in brass with spring wound mechanical movement telling time via turtle (missing) in pond pointing to chapter ring, c1935

Gubelin Swiss turtle mystery clock in brass with spring wound mechanical movement telling time via turtle (missing) in pond pointing to chapter ring, c1935 no turtle, light spotting to brass in otherwise good condition, ticks. When present, the turtle floats in bowl and moves via magnetic attraction to the mechanism in the case below. (you put a half cup of water in the time "bowl". A plastic toy turtle with a little magnet glued in the base will do for the time indicator. Height 3 inches Diameter 6 1/4"