A microscopic mite Lorryia formosa. Arachnids are a class ( Arachnida) of joint-legged Invertebrate Animals in the subphylum Chelicerata.

Micro-animals are animals that are microscopic and thus cannot be seen with the naked eye. All these microorganisms are multicellular but none are vertebrates. A microorganism (also spelled micro organism or micro-organism and also called a microbe) is an Organism that is Microscopic (usually Vertebrates are members of the Subphylum Vertebrata, Chordates with backbones or spinal columns The grouping sometimes includes Microscopic arthropods include dust mites, and spider mites, while microscopic crustaceans include copepods and the cladocera. Arthropods are Animals belonging to the Phylum Arthropoda (from Greek ἄρθρον arthron, " Joint " The house dust mite (sometimes abbreviated by Allergists to HDM) is a cosmopolitan guest in Human habitation Spider mites are members of the Acari (mite family Tetranychidae, which includes about 1600 species Structure of crustaceans As Arthropods crustaceans have a stiff Exoskeleton, which must be shed to allow the animal to grow ( Ecdysis or molting Copepods are a group of small Crustaceans found in the sea and nearly every freshwater habitat and they constitute the biggest source of protein in the oceans Cladocera or cladocerans are small Crustaceans commonly called Water fleas, part of the Class Branchiopoda. Another common group of microscopic animals are the rotifers, which are filter feeders that are usually found in fresh water. The rotifers make up a Phylum of microscopic and near-microscopic pseudocoelomate Animals They were first described by Rev