Page:Popular Science Monthly Volume 46.djvu/786

766 curious, generalized type, the Dromas ardeola, that web-footed, long-legged, black and white bird found on the shores and some of the islands of the Indian Ocean. At different times ornithologists have placed this form not only in various families, but in various orders. It has even been associated with the terns, and Sharpe has said it "is in habits a plover, in many points of structure larine [gull], but it burrows in the sand and lays a white egg, like that of a petrel—surely a combination of characters which demand that it shall have a separate rank as the representative of a definite suborder." British ornithologists call it the "cavalier," and place it near the stilts.

Again, we have the "pratincoles," all of the single genus Glareola, which are curious little ploverlike birds which have a flight resembling that of the swallows, and, like them, they feed upon the wing. There are nine or ten species of these, being found in Europe, Asia, Africa, and even Australia. They are distinguished for their trim build and marked delicacy in the coloration of their plumage. They nest upon the ground. With the gull group, the plovers are beautifully linked by those very types of outliers, the sheathbills of the genus Chionis. Among the limicoline birds their nearest allies are seen to be the oyster catchers, while their structure goes to show that, besides the gulls, they have affinities with a number of other groups. Sheathbills are of great interest to the ornithologist, as they are undoubtedly the descendants of very ancient and generalized types. There are at present only two species of them known—the one, C. minor, from the Kerguelen Islands, and the other, C. alba, from some of the islands of the antarctic seas. In life they somewhat resemble pigeons, and both species are pure white in plumage, while they receive their English name from the little saddle of horn ensheathing the base of the upper part of the bill. Numbers of their eggs have been taken, and they are said to resemble those of a plover. Chionis lives upon shellfish and certain sea weeds, and some authorities aver that they have been known to eat the eggs of other birds. Unanimity of opinion among naturalists as to their systematic position as yet by no means exists, and a thorough examination of their anatomy is still a thing much to be desired.

Returning once more to the neighborhood of the rails and