<unk> s are members of the subphylum<unk> , chordates with backbones or spinal columns. The grouping sometimes includes the hagfish, which have no<unk> , but are genetically quite closely related to lampreys, which do have<unk> . For this reason, the sub-phylum is sometimes referred to as "Craniata", as all members do possess a cranium. About 58,000 species of<unk> s have been described.<unk>  is the largest subphylum of chordates, and contains many familiar groups of large land animals.<unk> s comprise cyclostomes, bony fish, sharks and rays, amphibians, reptiles, mammals, and birds. Extant<unk> s range in size from the carp species Paedocypris, at as little as 7.9 mm (0.3 inch), to the Blue Whale, at up to 33 m (110 ft).
Vertebrate
Human
Arthropod
Geothermal
Cathartic
Metal
Keloid
Plastic