…a group of primitive jawless vertebrates that includes the lampreys, hagfishes, and many fossil fishlike forms…
…a group of primitive jawless vertebrates that includes the lampreys, hagfishes, and many fossil fishlike forms…
…an eellike, jawless vertebrate with a round sucking mouth, formerly included in a group with the lampreys and hagfishes…
…an extinct jawless fish of the Cambrian to Devonian periods, having a heavily armored body…
