Life in the Southern Isles; or, Scenes and Incidents in the South Pacific and New Guinea (1876) by Rev. William Wyatt Gill, published by the Religious Tract Society of London.
Since this is one of the earliest reports of tree octopuses of which I can reasonably own an original -- I don't think I could afford an original scroll by Athenaeus of Naucratis if one even existed -- and Gill was the first to bring Polynesian tree octopuses to the unfortunately disinterested attention of the scientific establishment, I acquired a copy for my collection.
I thought I'd share the cover since it's fairly attractive (although sadly devoid of tree octopuses). Click the image above for a larger composit scan of the front, back, and spine. You can also read the scanned text on Google Books.