"Diagram of a lateral view of a longitudinal section of Limulus. Suc, Suctorial pharynx. al, Alimentary canal. Ph, Pharynx. M, Mouth. Est, Entosternum. VS, Ventral venous sinus. chi, Chilaria. go, Genital operculum. br1 to br5, Branchial appendages. met, Unsegmented metasoma. Entap4, Fourth dorsal entapophysis of left side. tsm, Tergo-sternal muscles, six pairs as in Scorpio. VPM1 to VPM8, The eight pairs of veno-pericardiac muscles." — The Encyclopedia Britannica, 1910

Limulus

"Diagram of a lateral view of a longitudinal section of Limulus. Suc, Suctorial pharynx. al, Alimentary…