Jovan Hadži theories of animal evolution. He devised a system of classification in which he divided the animal kingdom into six phyla: Protozoa, Parazoa, "Ameria" (animals with no segments), "Oligomeria" (animals with few segments), "Polymeria" (animals with many segments) and Chordata. His choice of characters important for classification was generally discredited by his contemporaries, and the system was never accepted by zoologists. However, due to its simplicity, the system was widely used in science education in former Yugoslavia. His other major theory was that of the origin of metazoa - he developed an existing hypothesis stating that the first multicellular animals resembling
Bacterial phyla used for phyla, but generally the name of the phylum is generally the plural of the type genus, with the exception of the "Firmicutes", "Cyanobacteria", and "Proteobacteria", whose names do not stem from a genus name ("Actinobacteria" instead is from "Actinomyces"). The "Acidobacteria" (diderm Gram negative) is most abundant bacterial phylum in many soils, but its members are mostly uncultured. Additionally, they are phenotypically diverse and include not only acidophiles, but also many non-acidophiles. Generally its members divide slowly, exhibit slow metabolic rates under low-nutrient conditions and can tolerate fluctuations in soil hydration. The "Actinobacteria" is a phylum of monoderm