Name
- MacKenzie, Morell, physician1
- Macleay, George, Knight, politician and explorer, 1809-18911
- Macoun, John, Canadian botanist1
- Macpherson, Hugh Alexander, naturalist1
- Majendie, Vivian Dering, KCB1
- Major, Richard Henry, Keeper of Printed Maps and Plans British Museum1
- Malaiss, Constantin, palaeontologist1
- Mantell, Gideon Algernon, FRS, geologist1
- Marcou, Jules, geologist1
- Margerie, Emmanuel Jacquin de, French geologist1
- Marr, John Edward, geologist1
- Marschall, August Friedrich, Count1
- Martelli, Ugolino, of the Botanical Garden, Florence1
- Martin, Francis Pitney Brouncker, Wadham College, Oxford; MA 18431
- Maskelyne, Mervyn Herbert Nevil Story-, minerologist, politician and photographer, 1823-19111
- Masters, Maxwell Tylden, FRS, botanist1
- McClintock, Francis Leopold, Admiral KCB1
- McCormick, Robert, naval surgeon1
- McIntosh, William Carmichael, zoologist1
- McMahon, Charles Alexander, Major-General1