The growth of our knowledge of the gigantic extinct birds of Madagascar has been a very slow one. The first notice of their occurrence was published in 1851 by I. Geoffrey St. Hilaire; but it is only within the last two or three years that any part of their skeleton, except the bones of the leg and some very imperfect vertebrae, has been described. Eecently, however, the collections that have reached the Museum of Natural History at Paris, and those obtained by Dr. Forsyth Major for the British Museum, have filled most of the gaps, and all the important parts of the skeleton are now known.