A plate from Charles Darwin's Monograph on the Cirripedia, 1854, engraved by George Brettingham Sowerby, Jr.The bay barnacle, Balanus improvisus, described by Charles Darwin, on a shell of the sand gaper clam Mya arenaria
^Darwin, C. R. 1851 [=1852]. Living Cirripedia, A monograph on the sub-class Cirripedia, with figures of all the species. The Lepadidæ; or, pedunculated cirripedes. London: The Ray Society. Volume 1.
^Darwin, C. R. 1854. Living Cirripedia, The Balanidæ, (or sessile cirripedes); the Verrucidæ. London: The Ray Society. Volume 2.