Keywords: Origin of Vertebrates Fig 066.png Fig 66 ”Section through Branchial Appendage of Limulus br cart branchial cartilage; v br branchial vein; b s blood-spaces formed by branchial artery; P pigment; m<sub>1</sub> posterior entapophysio-branchial muscle; m<sub>2</sub> anterior entapophysio-branchial muscle; m<sub>3</sub> external branchial muscle 1908 The Origin of Vertebrates https //archive org/details/originofvertebra1908gask Walter Holbrook Gaskell PD-old-auto-1923 1914 Origin of Vertebrates book Limulus polyphemus anatomy |