Page:Natural History, Birds.djvu/232

Rh internal surface very irregular. In this organ it is that the food is elaborated by the parents before it is conveyed to the young; for a milky fluid of a greyish colour is secreted and poured into the crop among the grain or seeds undergoing digestion, and a quality of food suited to the nestling is thus produced. The fluid coagulates with acids and forms curd; and the apparatus forms, among the birds, the nearest approach to the mammae of the Mammalia"

The form of the Pigeons and their motions are graceful and elegant: the head is small in proportion, the body plump and rounded, the plumage full, compact, and smooth. The prevailing hues in the typical genus are various shades of blue and grey, merging into purple on the one hand, and into white on the other; in the Oceanic Pigeons green is the ordinary colour, varied with brilliant yellow. Metallic reflections of great beauty are common in the Family; not generally spread over the whole plumage, but confined to particular parts, and more especially the region of the neck. The expression of the countenance is peculiarly meek and gentle, and the eye large, liquid, and engaging. The voice, though frequently loud, has a soft and mournful character; it is known by the term cooing. The geographical distribution of the Family is very extensive, the form occurring almost every where, except within the frigid zones. The species also are very numerous; and are most abundant in the south-eastern regions of Asia, and the great Oriental Archipelago.