"Section through cephalothorax of a crab. H., Heart; Te., extension of the tergum; ST., sternum; PL., pleuron; T., tendons; 1st W.L., insertion of first walking leg; Br., gill in gill-chamber; g., gut; d.a., descending artery; A., afferent branchial; E., efferent branchial." -Thomson, 1916

Crab Cephalothorax

"Section through cephalothorax of a crab. H., Heart; Te., extension of the tergum; ST., sternum; PL.,…