Figure 5 in Studies on spider respiration and circulation by Victor Willem

Figure 5. Heart of Pholcus, viewed dorsally (X 50). I, II, III, ostia with their peripyles; aa, anterior aorta; ap, posterior artery; the origins of the 3 pairs of lateral arteries are assumed to be seen in transparency; a, 3rd pair; V1, pulmonary vein, indicated on a horizontal section passing at the level of the anterior pylocardia; V2, V3, two lateral veins and peripyles; c, posterior commissural ligament.