Another major vertebrate project was a monograph on the comparative anatomy of the vertebrate shoulder-girdle (pectoral girdle). One of the chief results of this work was, by demonstrating the true homologies of the various bones of the shoulder-girdle in fishes, to overthrow Owen's theory of the nature of limbs. Parker showed (contrary to Owen) that the true shoulder-girdle is from the first totally independent of the skull. In teleost and ganoid fish, the skull and shoulder-girdle are brought into connexion by derivatives of the skin-skeleton, not by bones of the shoulder-girdle. Discoveries like this alerted Parker to the failure of the great system of transcendental anatomy which Owen had done so much to establish.