The radula of nine cephalopods are compared on the basis of scanning electron microscopic observation and morphological measurements .Results indicate that all of them consist of 7 longitudinal rows of teeth :a median tooth and the 1st , 2nd , and 3rd lateral or lateral , inner marginal , and outer marginal teeth .The formula of radula is 3·1·3 .Sepioidea (Sepia robsoni , S .esculenta , S .pharaonis , S .latimanus , S .aculeata , Sepiella maindroni , Euprymna berryi)has only one cusp in the median tooth , and a marginal plate is absent .The median tooth has 3 and/or 5 cusps and marginal plates are found in the two species of Octopus ocellatus and O .variabilis .Other differences in the radula structure among the nine species are illustrated in detail .The relationships of radula of the cuttlefishes , octopuses and squids are discussed .It is suggested that radula should be thought in the cuttlefish taxonomy .