Alfred Edwin Eaton, curate and naturalist, obtained the degree Bachelor of Arts (BA) at the University of Cambridge in 1868. He was a keen entomologist and in 1870 contributed that part of R. McLachlan's Catalogue of British Neuroptera dealing with the Ephemeridae (mayflies). Years later he published a substantial "Revisional monograph of recent Ephemeridae or mayflies", in the Transactions of the Linnean Society (Zoology) (1883-1888, 352p). In 1892 he also described the Ephemeridae of Central America in Biologia centrali-americana (1892-1908). Many other papers by him, published from 1866 onwards, dealt with the anatomy and systematics of insects, particularly the Ephimeridae, including collections of the latter from Great Britain, India, Japan, New Zealand and Algeria. One paper contained notes on the fauna of Spitzbergen (1873), which he must have visited. Another series of papers, published during 1893-1898, dealt with the British Psychodidae (moth flies and sand flies).
In 1874 Eaton was chosen as naturalist of a British expedition to Kerguelen Island (in the southern Indian Ocean, 49º S, 69º E), sent out to observe the transit of Venus on 8 December that year. The expedition, led by Captain Fairfax and sailing in the ships Volage and Supply, arrived at the Cape in the last week of July 1874 and stayed for more than a month. During this time Eaton collected algae, fungi and lichens around Cape Town on the recommendation of Sir J.D. Hooker* of Kew Gardens, and organised the capture of rabbits for release on Kerguelen. His fungi were enumerated by Berkeley in 1876 and included six new species, two of which, Galera eatoni and Daedalea eatoni were named after the collector. The lichens, most of which were collected on the slopes of Table Mountain, were enumerated by Crombie in 1876. Of the 96 species as many as 34 were new, as only one earlier significant collection of Cape lichens had been described, made by H. Wawra*. A list of his Cape Hepaticae (liverworts) was published by W. Mitten in the Journal of the Linnean Society (Botany) in 1877.
The expedition left the Cape during the first week of September, leaving the astronomer A. Marth* behind to observe the transit at the Cape. The party stayed at Kerguelen from 11 October 1874 to 27 February 1875. They were joined there by transit expeditions from Germany and the United States of America. Eaton made extensive collections of the fauna and flora of the island and surrounding sea.