"Ape and Tiger" methods, [265]

Appendicularia, [56], [57]

Apprenticeship in medicine, [183]

Archæopteryx, [136]

Archetype of molluscs, [58], [59], [61]

Archetype of Vertebrata, Articulata, and Radiata, [62]

Arctogœa, [140]

Argyll, Duke of, [248]

Aristotle, [100], [259]

Arnold, Matthew, [185]