John Hemsworth Osborne-Day, English-born South African marine biologist (Sussex, England 25 August 1909 – Knysna 24 April 1989)

Authority internationally recognized on the ecology of estuaries and coastal waters as well as on the taxonomy of polychaete worms

DESCRIBED POLYCHAETA GENERA

Anguillopsyllis 1963

Capitobranchus 1962

Drilognathus 1960

Exogonoides 1963

Lamellisyllis 1960

Leitoscoloplos 1977

Micronereides 1963

Neovermilia 1961

Orbiniella 1954

Pharyngeovolvata 1951

Proscoloplos 1954

Scoloplella 1963

Terebellobranchia 1951

Telothelepus 1955

Unanereis 1962

HONORS 

Dayellus Inglis 1964 (Nematoda)

Dayipsammolyce Pettibone 1997 (Annelida Polychaeta)

Dayius Steiner & Amaral 1999 (Annelida Polychaeta)