PROPOSALS FOR A RETURN TO THE ORIGINAL DE FINITION OF HOMOLOGY THROUGH THE CHAETOTAXIC ANALYSIS OF COLLEMBOLA

A taxonomic study on the Collembola raises several problems on the top ic of homology. In one basic point of our argument, we claim that the question on the definition of homology cannot be resolved in a general way, but needs to be in accordance with the facts resulting from the taxonomic research. It is then possible that an ornithologist would gi ve a slightly different meaning to the word homology than would a coll embologist. For instance, the study on Collembola raises the problem o f significance of chaetotaxic structures for distinguishing organs. Th is step seems to be fundamental as well as distinct from research in p hylogenetics. Incorporating the concept of homology into this first st ep involves a return to the classical definition of homology which is the similarity of relative position, and connections of one organ in r elation to other organs. The case of vertitional (probabilistic) organ s raises another problem. After examining the case where the probabili ty is equal to zero, we propose to apply the concept of homology to th e nodes of a chaetotaxic network.