Bill stout, curved at tip, upper mandible longer than the lower. Nostrils-oblong, at some distance from base of mandible. Tarsus scutellated in front. Anterior toes fully webbed. Hind toe small, free, and raised (webbed to tarsus in Leucophaeus and Pagophila ; rudimentary or obsolete in Rissa). Tail square,, or nearly so (forked in Xema ; cuneate and mid pair produced in Rhodostethia).
(i.) Tail square, or very nearly so. Hind toe free.