The original description commences: "The new species which we owe to the researches of M. G. Muller, and which we shall name _Ae. mulleri_, is smaller. Nevertheless, it is superior in size to _Ae. hildebrandti_, described by M. Burckhardt, which also came from Antsirabé. We possess the almost complete skeleton of this bird, the skull, mandible, vertebrae, ribs, sternum, a part of the pelvis, the leg bones, and a few phalanges of the pes; so that we can now exactly define the position and affinities of the genus _Aepyornis_." Then follows the diagnosis of the family, which I have given before. Habitat: Central Madagascar. AEPYORNIS MODESTUS M.-E. & GRAND. _Aepyornis modestus_ Milne-Edwards & Grandidier, Ann. Sci. Nat. (5) XII, p. 189 (1869). Messrs. Milne-Edwards & Grandidier state at pages 180-181 that the bone (a portion of a femur) which is the type of the above name, had a shaft-circumference of 120 mm., while in _Ae. medius_ this circumference was 215 mm., and in _Ae. grandidieri_ (= _maximus_ auct. nec. Geoffroy), it was 270 mm. Type locality: Amboulitsate, in West Madagascar. {231} MULLERORNIS MILNE-EDWARDS & GRANDIDIER. Birds of medium size, not having the heavy and massive build of _Aepyornis_. They appear to resemble more closely the _Casuaridae_. Known only from leg bones. Number of species: 2. MULLERORNIS BETSILEI MILNE-EDW. & GRAND. _Mullerornis betsilei_ Milne-Edwards and Grandidier, Compt. Rend., CXVIII, p. 125 (1894). Original description as follows:--"The leg bones are slender, the tarso-metatarsus is not enlarged as in the preceding genus, and the section through the shaft shows almost an isosceles triangle. The bone itself having more the proportion of _Dromaius_. "Length of tibio-tarsus 390 mm. Circumference of tibio-tarsus 90 " Width of tibio-tarsus 30 " Width of proximal end 75 " Width of distal end 60 " Length of tarso-metatarsus 310 " Circumference of tarso-metatarsus 80 " Width of shaft of tarso-metatarsus 27 " Width of proximal end 70 " "_Mullerornis betsilei_ inhabited the same area as _Ae. mulleri_ but was much rarer. (Translated.)" Habitat: Central Madagascar. {232} MULLERORNIS AGILIS MILNE-EDW. & GRAND. _Mullerornis agilis_ Milne-Edwards and Grandidier, Compt. Rend., CXVIII, pp. 125-126 (1894). Original description as follows:--"_M. agilis_ inhabited the South-west Coast; we only possess, of this species, one tibia, which is remarkable for the manner in which the intermuscular bony ridges and the tendon-grooves are marked. The exterior border of the bone above the lower articular surface has developed into a very pronounced crista." (Translated.)