Relationships between specialized cells, capillaries and intermediary cytofibrillary elements. Xth Note. Biological evolution of the emonctory subsystem and stereotype in invertebrates.

The paper points out the importance of homeostasis as the most general system of the organism (Ist order system) and the 2nd order subsystem which composes it, discussing the relations between them and the biological evolution of the emonctory subsystem in protists and invertebrates. The emonctory structures, functions and stereotype and their component parts are studied in protists, spongia, coelenterata and coelomata: lower worms, annelids, their hyponeurian descendents (arthropods, molluses) and epineurian descedents echinoderms and protochordates (Stomochordata, Tunicata, Cephalochordata). The structure, functions and stereotypes of protonephridia and metanephridia and of substitutive (vicarious) emonctory organs (nephrocytes and peritoneal cells) are studied in coelomatic invertebrates. Their evolution appears to be directioned to localize within the limits of the emonctory subsystem. During their evolution, some nephridial functions are performed by the vicarious emonctory organs. The evolution of the subsystem in invertebrates appears to be based on stable characters and their relationships with variable features.