Much larger than these, being sixteen to twenty-one inches long, are the Oyster-catchers (Hcematopus), a maritime, nearly cosmopolitan group of a dozen species, so named from the fact that with their strong, compressed, almost knife-like bills they are able to force open the shells of clams, mussels, etc. They have very robust legs and feet, the hind toe being absent, and the tarsus reticulated on both front and back, while the plumage is largely black above, or in some species black throughout, and white below; the bill is bright red in life. In the American. Oyster-catcher (H. palliatus) the rump is of a brownish slate-color, like the back and wings, and the iris bright yellow; while in the European Oyster-catcher (H. ostralegus) the rump is entirely white and the iris crimson. The former ranges along the seacoasts of temperate and tropical America from Nova Scotia and Lower California to Brazil and Patagonia, and the latter along the coasts of Europe and parts of Asia and Africa, occasionally reaching Greenland. The Oyster-catchers frequent the sandy beaches, usually in small parties, and are rather shy and difficult of approach. When in repose they walk with a stately step, but they can run with ease and swiftness, and when pressed soon take to wing and with swift flight pass out of sight around some projecting point. They feed largely on shell-fish. The nest is a mere depression in the sand, and the eggs, usually three in number, are buffy white spotted and blotched with chocolate. The female, it is said by many observers, only sits on the eggs at night or during dark days, otherwise leaving the sun and hot sand to perform the work of incubation. In the Black Oyster-catcher (H. bachmani) of the Pacific coast of North America the plumage is entirely blackish; its habits are similar to those of the forms already mentioned. Other species are found in eastern Asia, New Zealand, Australia, Africa, and southern South America.