A static form has the following properties. The boundary of its support is generally not complicated, being locally polyhedral, and it is comparatively rigid and insensitive to perturbations. The great interest of the mean field is to show that converging funnelling mechanisms, with successive discontinuous corrections, a priori of a finalist nature, can occur naturally and in a structurally stable fashion. The concept of the generalized catastrophe can be relevant even when there is, strictly speaking, no morphogenesis. The idea of a chreod differs from the more general idea of the morphogenetic field only in the privileged role allotted to time and its orientation. The examination of the corpus of an empirical morphology often shows that certain aggregates of elementary chreods occur very frequently or exhibit a high degree of stability. The foundation of the corpus is the primordial essential task of the experimenter, and many sciences, particularly biology, have scarcely passed the stage.