Keywords: Origin of Vertebrates Fig 091.png Fig 91 ”Sagittal Median Diagrammatic Section through the Operculum of the Male Thelyphonus From Tarnani The thick line is the operculum composed of two segments I and II Ut Masc uterus masculinus; Gen Ch genital chamber; Int Op internal opening; Ext Op external opening common to the genital and respiratory organs 1908 The Origin of Vertebrates https //archive org/details/originofvertebra1908gask Walter Holbrook Gaskell PD-old-auto-1923 1914 Origin of Vertebrates book Thelyphonus |