_Megalapteryx tenuipes_ Lydekker, Cat. Foss. Birds Brit. Mus. p. 251 (1891). This species was described from the tibio-tarsus, which is longer and relatively more slender than in _M. hectori_. Its distal width is about one-ninth of its length, while in _M. hectori_ it is about one-seventh. The length of the tibio-tarsus is approximately 0.405 mm. = 16 inches, and width of distal extremity about 0.044 = 1.74 inches. Type specimens Nos. 49989 and 49990, British Museum. Habitat: Middle Island, New Zealand, and perhaps North Island. (Type locality Lake Wakatipa, Queenstown, Otago.) Complete skeleton in the Tring Museum. Mr. Lydekker mentions also a right femur from the North Island, of the same proportions as those of _M. tenuipes_ and 0.255 m. (= 10.1 inches) long. It may probably belong to a different form, as we know _M. tenuipes_ otherwise only from the Middle Island. {199} MEGALAPTERYX HUTTONII (OWEN). (PLATE 41.) _Dinornis huttonii_ Owen, Ext. Birds, N.Z., p. 430 (1879). _Dinornis didinus_ Owen, Trans. Zool. Soc. XI, p. 257 (1883). _D. didiformis_ Haast, (non Owen 1844) Trans. N.Z. Inst. I, p. 83, Nos. 5 & 6 (1869). _Mesopteryx didinus_ Hutton, Trans. N.Z. Inst. XXIV, p. 129 (1892). The synonymy of this form is somewhat confused, but I think it is clear that _huttonii_ of Owen is its proper name. Professor Owen (Ext. B. p. 430) says: "In the collection from the Glenmark Swamp, South Island, are bones that scarcely differ, save in size, from the dimensions (? W.R.) of the type bones of _Dinornis didiformis_ from the NORTH ISLAND. They are noted as of a large variety of that species." Captain Hutton remarks: "The bones that I have arranged under the name _D. didiformis_ belong probably to a new species. The tibia is well marked and quite distinct, but the femur and metatarsus, that I have associated with it, pass almost into _D. casuarinus_, but are rather smaller. _D. casuarinus_ is undoubtedly a good species, easily distinguished by its tibia." Possibly the _Dinornis_ of the SOUTH ISLAND, with the tibia characteristic of _D. didiformis_ of the NORTH ISLAND, may need to be noted for the convenience of naming the bones as _Dinornis huttonii_. When describing his _D. didinus_, Professor Owen failed to recognise its identity with his previously named _D. huttonii_, doubtless owing to the leg bones being hidden by the dry integument. This being the case, it is necessary to reinstate the name _huttonii_, as it has four years' priority over _didinus_.