Because watermelons vary in size and shape, your yield from the following recipe may differ from ours. We began with a fourth of a large watermelon. When slicing the watermelon, aim for a minimum of four slices but be aware that you could have as many as six, depending on the configuration of your melon; a long, narrow watermelon will give more slices than a fatter, rounded one.
04Discard real seeds from watermelon to yield 5 cups. In a saucepan heat 1 cup purée with sugar over moderate heat, stirring, until sugar is dissolved and stir into remaining purée with lime juice and liqueur. Chill mixture, covered, until cold.
05Freeze sorbet in an ice-cream maker. When sorbet is frozen to a thick slush add three fourths of chocolate "seeds" and continue to freeze until frozen.
06Working quickly, fill frozen watermelon rinds with sorbet, smoothing it with a rubber spatula. Arrange remaining chocolate "seeds" realistically on slices and smooth _sorbet_again. Cover sorbet with plastic wrap and freeze until very firm, about 6 hours. (Watermelon sorbet slices may be made 3 days ahead and kept frozen, wrapped tightly).