The history of biology is replete with examples of how comparative biology helped clarify the meaning of structure and function in complex animals. Indeed, without the comparative approach to biology, the birth of physiology would have been delayed. Fishman (1979) Comparative morphologists are challenged to discern the changes that have occurred in evolution and development of the forms and states of organisms as well as to explain the factors that compelled them (e.g. Dullemeijer 1974). The main objective of this contribution is to present what I deem to be some of the fundamental structural...

1 Introduction 1. 1 General Remarks The connective and supportive tissues constitute a considerable amount of the biomass in human and animal organisms. Characteristically, the osseous, car- laginous, and ?brous tissues each connect a vital part (cells) with a non-vital part, i. e., extracellular matrix (ECM). The composition of the ECM constitutes the mechanical qualities of the respective tissue. The functional role of the bone and cartilage tissues is exhaustively discussed in the relevant literature. Whereas bone tissue provides the static and dynamic stability of the system as a whole,...

The aim of this study was to investigate the development and diffferentiation of the adrenal glands in the grass snake during early stages of ontogenesis. After light microscopy and ultrastructural investigation, six developmental phases were distinguished in the grass snake adrenal glands. Similar developmental phases were described in pig embryos but they slightly differ from those presented above. In reptile and mammal embryos a similar direction of changes is observed in primaordia of both tissues forming adrenal glands.