Jennifer Dunning for The New York Times

ROLAND BARTHES explores the mythic underpinnings of everyday rituals in ''Mythologies,'' finding signs and symbols in the most ordinary of experiences. Three of his essays served as inspiration for Mark Morris's ''Mythologies,'' an evening of recent dances presented by the Mark Morris Dance Group on Friday at the Manhattan Center's Grand Ballroom. But Mr. Morris, though a master of the kind of telling exaggeration about which the French semiologist writes, reverses the process of Barthes's exploration. In collaboration with his impressive dancers and Herschel Garfein, a composer, he constructs a world of inseparable spectacle and symbol.