Page:Popular Science Monthly Volume 46.djvu/783

Rh types, the student will there be confronted with at least two families, the exact position of either of which has more or less puzzled the ornithologist—I refer to the megapodes and those curious little quail-like birds the hemipodes or "button quails." The former leave their eggs to be hatched without incubation, simplyburying them in the ground as many reptiles do, or heaping over them a mound composed of leaves, earth, and other materials. There are several species and genera, and the chicks of all are highly developed at birth Again, these gallinaceous types, or the "fowls" or "chicken types," including as they do everything after the fowl order, as turkeys, pheasants, quails, peacocks, and a perfect host of related kin, are beautifully linked with the pigeons through the true intermediate forms—the sand grouse.

The sand grouse are small, columbo-partridge forms given to remarkable erratic migrations over certain parts of Europe and Asia. Related to the pigeons we have the extinct dodo, and the nearly extinct "tooth-billed pigeon" of the Samoan Islands (Didunculus strigirostris). Other birds possessing galline affinities are the well-known curassows, and they in their general appearance somewhat remind us of the curious "hoactzin,"! one of the veriest "outliers" among birds in existence.

Even at the present writing, avian taxonomers are by no means agreed upon the question of the exact relationships of this bird. Buffon placed it among the curassows, while Gmelin and others arrayed it with the pheasants. Early in this century Illiger created for it the genus it now occupies, since which time it has received the closest possible attention from ornithotomists in various parts of the world.

Opisthocomus has a size about equal to the chachalaca of our Texan border, and is extremely remarkable in its anatomy, its appearance, its nesting, and its habits. It is found in tropical South America, and but the one species of it is at present known.