The paper reviews the representational formats that are currently in use in Cognitive Semantics for the diagrammatic representation of the semasiological structure of lexical items. Three major types of representation will be distinguished: the radial set model popularized by Lakoff (1987), the schematic network model defined by Langacker (1987, 1991), and the overlapping sets model introduced by Geeraerts (1989b). It will be argued that (given a number of straightforward adaptations and additions), these three models are notational variants, in the sense that they exhibit the same representational potentialities. This conclusion will be reached by examining whether the three models can provide for the representation of (our different types of data that arise from a prototype-theoretical conception of semantic structure. These four types of data are: salience effects among readings, non-hierarchical semantic links among readings (like metaphor and metonymy), hierarchical semantic links among readings, and discrepancies between intuitive and analytical definitions of polysemy. (Dirk Geeraerts)