[Individual variation in the development of the common toad, Bufo bufo (Anura, Bufonidae): 3. Limitations of individual variation and their causes].

The results of studies on the axial skeleton of the common toad (a model species) have been used to analyze factual limitations of individual variations. The results show that the states of the studied characters do not freely combine with each other but are subject to certain morphogenetic limitations. The causes of most these limitations have been revealed during the study. Classification of the main factors limiting individual variation in the course of development is presented.