Darwin and cirripedology
Charles Darwin (1809–1882) (Fig. 1) began his work on barnacles in 1846, about 20 years after they were recognized if not fully accepted as crustaceans. Needless to say, knowledge of their systematics and morphology was in an early stage of development. Thus Darwin took on a substantial challenge, applying what we now call the ‘Darwinian Method’ (Ghiselin 1969). He looked at barnacles from every vantage point including using the best dissecting and compound microscopes available at the time. Much of the work required delicate anatomical dissections on minuscule animals because embedding and cutting of thin sections would not come into use until the 1860’s. His studies included larval development and metamorphosis as well as adult morphology. He became intensely interested in their sexuality, powers of burrowing, method of flotation, and fossil record, and he created a nomenclature of their soft as well as their hard parts in order to discuss them in sufficient detail. Darwin’s four volumes on barnacles were divided two each between fossil and living Cirripedia (1851, 1852, 1854, and 1855; or FC 1, LC1, LC2 and FC2, respectively, where cited herein). In these works, he not only elucidated barnacle crustacean affinities, functional morphology, and evolution, but he also established the basis for much of the classification we use today. When questions arose that would not yield to observation, he applied deduction that often led to novel hypotheses to fill the voids. Many of Darwin’s deductions and ideas, today dismissed as totally bizarre, were not at all out of keeping with knowledge of the times.