Figure 6 in REVIEW How the discovery of oligochaete regeneration during the Enlightenment was pivotal to the advancement of annelid research

Figure 6. Circulatory apparatus of the earthworm as depicted in Spallanzani's laboratory notebooks (Spallanzani, 2003). A, mid-body dorsal dissection showing the dorsal vessel (ef) running above the gut and giving off segmentally paired median (xx) and adseptal (rr) branches. B, the richly vascular 'gizzard' (= calciferous glands); (qo) dorsal vessel, 'having two lateral branches which spread blood threads laterally, that by their parallelism do a beautiful work'. C, the ventral nerve cord and branched lateral nerves. D, the subneural vessel and lateroneural blood vessels, giving off branches at internodes and nodes of nerve cord, respectively. E, the ventral blood vessel (ao) and its five paired lateral 'bags' (= oesophageal hearts) (cc, dd, ee, ff and gg) descending from the dorsal vessel: 'blood can very openly be seen filling the bags of the back one after the other, which at that time become bigger and swollen, and this swelling is seen progressing up to the last dorsal bags. If then the earthworm turns its belly, then one can see in the belly bags an equal swelling'. F, the ventral blood vessel and its sinuous course in comparison to the straight course of the subneural vessel, seen in vivo by transparency.