Botany - Animal Kingdom Question with Solution | TestHub

The diagram represents the class Cyclostomata. The body is elongated, eel-like with median fins and cartilaginous fin ray. The paired appendages are absent, tail is diphycercal. Skin is soft, smooth and containing unicellular mucous glands, but no scales are present. Notochord persists throughout life. Imperfect neural arches over notochord represent rudimentary vertebrae. The mouth is ventral, suctorial and circular with denticles. In lateral sac-like pouches of the pharynx, 5-16 pairs of gills are present, while gill-slits are present in 1-16 pairs. Air bladder is absent, and they are mostly poikilotherms.