Closely related to the fur seals are the much larger animals popularly known as sea-lions. These still exist in great numbers in south temperate waters. Both are distinguished from the hair seals by one obvious characteristic: their method of propulsion on land is by a "lolloping" motion, in which the front and hind flippers are used alternately. The hair seals move by a caterpillar-like shuffle, making little or no use of their flippers; and so, the terminal parts of their flippers are not bent outwards as they are in the fur seals and sea-lions. Of the hair seals there are five varieties to be recognized in the far South. The Weddell seals, with their mottled-grey coats, are the commonest. They haunt the coasts of Antarctica and are seldom found at any distance from them. Large specimens of this species reach nine and a half feet in length. The crab-eater seal, a smaller animal, lives mostly on the pack-ice. Lying on a piece of floe in the sunshine it has a glistening, silver-grey skin--another distinguishing mark being its small, handsome head and short, thin neck. Small crustaceans form its principal food. The Ross seal, another inhabitant of the pack-ice, is short and bulky, varying from a pale yellowish-green on the under side to a dark greenish-brown on the back. Its neck is ample and bloated, and when distended in excitement reminds one of a pouter-pigeon. This rare seal appears to subsist mainly on squid and jelly-fish. The sea-leopard, the only predacious member of the seal family, has an elongated agile body and a large head with massive jaws. In general it has a mottled skin, darker towards the back. It lives on fish, penguins and seals. Early in April, Hurley and McLean were the first to obtain proof that the sea-leopard preyed on other seals. Among the broken floe-ice close beneath the ice-cliffs to the west of Winter Quarters, the wind was driving the dead body of a Weddell seal which swept past them, a few yards distant, to the open water. Then it was that a sea-leopard was observed tearing off and swallowing great pieces of flesh and blubber from the carcase. The last variety of hair seal, the sea elephant, varies considerably from the preceding. Reference has already been made to the species earlier in the narrative. The habitat of these monstrous animals ranges over the cold, south-temperate seas; sea elephants are but occasional visitors to the ice-bound regions. Although they have been exterminated in many other places, one of their most populous resorts at the present day is Macquarie Island. In the case of all the hair seals a layer of blubber several inches in thickness invests the body beneath the skin and acts as a conserver of warmth. They are largely of value for the oil produced by rendering down the blubber. The pelts are used for leather.