Jawless vertebrates

jawless vertebrates (Agnatha) and the
jawed vertebrates (Gnathostomata)
Agnatha ...

Although the classical molecules of the adaptive immune system (e.g. antibodies and T cell receptors) exist only in jawed vertebrates, a distinct lymphocyte-derived molecule has been discovered in primitive jawless vertebrates, ...

See also: Organ, Life, Invertebrates, Mammals, Invertebrate