Lampreys possess a large round sucker, lined with teeth, that surrounds the mouth and is used to feed on what?
marrow
parasites
herbivores
blood
Like hagfish, lampreys also lack scales, but they have fins and a partial backbone. The most striking feature of lampreys is a large round sucker, lined with teeth, that surrounds the mouth (see Figure below ). Lampreys use their sucker to feed on the blood of other fish species.