Correspondents include Sir Julian Huxley, King's College, London; Alan Greenwood, Institute of Animal Genetics, University of Edinburgh; Dr Anne Hosker, University of Leeds; B W Tucker, Department of Zoology and Comparative Anatomy, University Museum, Oxford; Prof. Frank Lillie, Division of Biological Sciences, University of Chicago; and other zoologists and ornithologists. Filed alphabetically by surname

File A-G. Contains various exchanges of correspondence between Paul 'Espinasse and other scientists. There is an extensive exchange between Espinasse and members of the Institute for Animal Breeding and Genetics in Edinburgh between 1937-1942. An exchange with a Mr Duncan of the Zoological Society of London regarding Espinasse's paper, probably entitled 'The Development of the Anatomy and Reactions of the Brown Leghorn Breast Feather', between Dec 1939- early 1940) concerns proofs and reprints, while another exchange between the pair relates to the initial reviewing of the paper, the date of 'Espinasse's presentation at the Society and proofs of his paper. Further exchanges include one with James Fisher of the British Trust for Ornithology in 1942; another with Munro Fox Editor of the Biological Reviews about 'Espinasse's MS on colour in feathers and an exchange with Honor Fell of Strangeways Research Laboratory on culturing feathers and testing hormones.

File H-Z. Contains various exchanges of correspondence between Paul 'Espinasse and other scientists. Includes correspondence with Koller of the Institute of Animal Genetics concerning possible reports on innervations of pigment cells; an exchange with PR Lowe of the British Museum relating to penguin feathers and an exchange with several correspondents concerning colour change in mature feathers. There is also an exchange with Arthur Walton of Strangeways Research Laboratory about the possibility of culturing feather germs and assorted correspondence to several people concerning plans for 'Espinasse's Biological Reviews article about feather growth and hormone action.