Gilles Deleuze and Raymond Ruyer have been sui generis morphologists. Their peculiar contributions to philosophical morphology can cast light on some problematic issues concerning the relationship between “form” and “formation”. In this respect, the musical concepts of «rhythm» and «melody» would play an important role insofar as to address respectively the problem of temporality of the living form and the problem of its events-based normativity. In the first paragraph, I address some morphological positions in Deleuze’s philosophy of creation, in relation (...) to his perspective on time and genesis. In the second paragraph I deal with Ruyer’s symmetrical view, which can provide further clarifications on the idea of biological constraints’ modification. The concepts of rhythmic pulsation and melodic orientation are shown to be two crucial coordinates in order to approach the intrinsic features of the living. (shrink)