"Diagrams of the meta-sternite st, with genital operculum op, and the first lamelligerous pair of appendages ga, with uniting sternal element st of Scorpio (left) and Limulus (right)." — The Encyclopedia Britannica, 1910

Meta-sternite

"Diagrams of the meta-sternite st, with genital operculum op, and the first lamelligerous pair of appendages…