Scientific Name: Agnatha Common Name: Jawless Fish
Characteristics: -Uses gills made up of feathery gill filaments that contain blood vessels to breathe -Two chambered heart, one chamber receives deoxygenated blood, the second pumps blood directly to the capillaries of the gills for oxygen - Reproduces sexually, fertilization and development is external in most Origin: Fossils of fishes that existed 500 million years ago have similar characteristics to present day fishes. Agnatha seems to be direct descendants of ostracoderms.