Marina Warner (LRB 09-Apr-2009) states that Edward Heron-Allen 'wrote the definitive work on barnacles'. Polymath that Heron-Allen undoubtedly was, as is usually the case in matters biological, the definitive work on barnacles is by Charles Darwin, namely his series of monographs on living and fossil cirripedia (1851-55).
Richard Carter, FCD
The Friends of Charles Darwin
See also: Royal Society podcast - The Singular Life of Edward Heron-Allen FRS (mp3)