The beautiful bird, the portrait of which is prefixed to the present article, is one of the rarest of its tribe, and has until very lately been confounded by ornithologists with the Hyacinthine Macaw, a fine but much less splendid species. It is figured by M. Spix in his Brazilian Birds under the name which we have adopted; but is there given without either characters or description. Its claim to generic distinction would seem to depend on the excessive length and powerful curvature of its claws and upper mandible, and on the slight developement of the toothlike process of the latter. Its colour is throughout of a deep and brilliant blue; the beak, legs, and claws, are black; and the cere and a naked circle round each of the eyes are of a bright yellow. Our specimen measures two feet four inches from the top of the head to the extremity of the tail, and the expansion of his wings is four feet. The length of the upper mandible is five inches, and that of the lower, two.…