English: From source: Waptia fieldensis Walcott, 1912 [10] from the middle Cambrian (Series 3, Stage 5) Burgess Shale, British Columbia, Canada; reconstruction of the post-maxillular cephalothoracic appendages. (a) Lateral views. (b) Mesial views showing endites along the inner margin of the 1st to 3rd appendages; first pair of appendages showing both limbs with converging endites. Podomeres 1–5 and 6–9 represent the endopod and the basipod, respectively. See also videos in electronic supplementary material, S23 and S24. All drawings at the same scale. Abbreviations are as follows; anu, annulus; cl, claw; en(6)-en(9), endite of the 6th to 9th appendage podomeres; lam, lamella; pma1–4, 1st to 4th post-maxillular cephalothoracic appendages; 1–9, 1st to 9th podomere of appendages.