Arrows indicate direction of blood flow.
1: all round perimeter, oxygen-depleted blood leaves foot and viscera in vessels which pass through gaps between bundles of pedal-retractor muscle.
2: blood oxygenated in pallial gills around entire perimeter.
3: oxygenated blood travels around perimeter in efferent pallial vessel.
4: oxygenated blood in efferent pallial vessels enters nuchal cavity at left.
5: position of heart within body. Heart receives blood via vessel through nuchal cavity and circulates it throughout the body.

OTHER SPECIES ALBUMS
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