Relationship between specialized cells, capillaries and intermediary cytofibrillary elements. XIth note. Biological evolution of the emunctory subsystem and stereotype in vertebrates.

This note completes in vertebrates the study of the emunctory subsystem and stereotype in invertebrates (Xth note). The theory of systems (and of open biological systems) of Bertalanffy, the theory of internal laws and limits of each organizational level (Needham) and the theory of biological stereotypes and of their morphofunctional expression (Mârza, Repciuc and Eskenasy) are also corroborated. In this light there were studied: the characters of the emunctory stereotype in vertebrates, its similar formation mode by three links (extracting, conveying and excretory links) as in the coelomatous invertebrates, and the passage of the emunctory stereotype from invertebrates to vertebrates. The present-day Acraniata and their offsprings, the Protocraniata, Agnatha and aquatic Gnathostoma, have an emunctory stereotype identical in its essential characters, without discrepancies between its links. The passage does not occur, however, from the metanephridia to the pronephros, but to the mesonephros. This latter reaches its highest functional limits in Dipnoi and Amphibia. The author indicates the mechanisms which, in its opinion, play a role in the activation of organo-genetic capacities of the metanephros in the caudal nephrogenic area. The importance of the three nephrogenic areas of the vertebrates, their succession and interdependence are also discussed. The problem of the archi(holo)nephros is critically reviewed, and the author's hypothesis that the glomerular ultrafiltrate and the coelomic liquid of invertebrates with metanephridia had the same composition and underwent the same processes of reabsorption-secretion is dwelt upon. A conclusion is drawn from these two notes, according to which stability--directed by the stabilizing selection--plays a directional role in the evolution of the new organizational levels, in the maintenance and development of the characters of the emunctory stereotype within the emunctory subsystem (EMSS). Between variability and stability strong relations are established and hereditarily transmitted.