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"View from below of a scorpion (Buthus occitanus) opened and dissected so as to show the pericardium with its muscles, the lateral arteries, and the tergo-sternal muscles. PRO, Prosoma. dpm, Dorso-plastral muscle. art, Lateral artery. tsm1, Tergo-sternal muscle of the second (pectiniferous) mesosomatic somite; this is the most anterior pair of the series of six, none are present in the genital somite. tsm4, Tergo-sternal muscle of the fifth mesosomatic somite. tsm6, Tergo-sternal muscle of the enlarged first metasomatic somite. Per, Pericardium. VPM1 to VPM7, The series of seven pairs of veno-pericardiac muscles. There is some reason to admit the existence of another more anterior pair of these muscles in Scorpio; this would make the number exactly correspond with the number in Limulus." — The Encyclopedia Britannica, 1910

Scorpion

"View from below of a scorpion (Buthus occitanus) opened and dissected so as to show the pericardium…