Sheathbill (chionis, Forst.), a genus placed by Gray among the gallinaceous birds, but by Latham, Cuvier, and Van der Hoeven among the waders. The bill is short, strong, compressed toward the tip, the culmen curved, and the base covered with a movable horny sub-stance, more or less concealing the nostrils; base of bill and cheeks covered with a warty naked skin; wings moderate, the second quill the longest, and the bend with a blunt knob; tail moderate and even; tarsi short, strong, covered with small rough scales; toes moderately strong, with transverse scales, the outer united to the middle one by a membrane at the base, and the hind one small, elevated, and on one side; claws short and blunt. The white sheathbill (C. alba, Forst.) is from 15 to 18 in. long; the plumage is pure white, the bill and knob of wing black; the legs bare a little above the joint, and reddish. It is found in New Zealand, Australia, and the islands of the Antarctic ocean, where it frequents the shores in flocks, searching for food, which consists of mollusks, sea weeds, and animal remains; numbers have sometimes been seen by southern voyagers at a great distance from land, resting on icebergs and feeding on refuse matters. The flight is like that of the pigeon; the flesh is said to be excellent.

With the general appearance of a gallinaceous bird, the sheathbill has the habits of a wader.