Distribution. Acanthamoeba spp. are among the most prevalent protozoa found in the environment. They are distributed worldwide, and have been isolated from soil, air, sewage, seawater, chlorinated swimming pools, domestic tap water, bottled water, dental treatment units, hospitals, air-conditioning units, and contact lens cases.
The Placozoa / p l æ k ə ˈ z oʊ ə / are a basal form of marine free-living (non-parasitic) multicellular organism. They are the simplest in structure of all animals. Three genera have been found: the classical Trichoplax adhaerens, Hoilungia hongkongensis, and Polyplacotoma mediterranea, where the last appears most basal.
Characteristics. The most notable shared characteristic is the presence of cortical (near the surface) alveoli (sacs). These are flattened vesicles (sacs) arranged as a layer just under the membrane and supporting it, typically contributing to a flexible pellicle (thin skin).
The Mesomycetozoea (or DRIP clade, or Ichthyosporea) are a small group of Opisthokonta in Eukaryota (formerly protists), mostly parasites of fish and other animals.
Ctenophora (/ t ə ˈ n ɒ f ər ə /; sg. ctenophore / ˈ t ɛ n ə f ɔːr, ˈ t iː n ə-/; from Ancient Greek κτείς (kteis) 'comb', and φέρω (pherō) 'to carry') comprise a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide.