The respiratory pigment you would find in a blue crab or octopus is hemocyanin. hemoglobin. hemophilin. ferritin. calmodulin.

The respiratory pigment you would find in a blue crab or octopus is hemocyanin. emocyanins are respiratory proteins occurring extracellularly in the hemolymph of some arthropods and molluscs. Although the hemocyanins from both stems have a similar oxygen-binding center, they have different structures.