Released Jan. 4, 1977, at Halley Bay, a British scientific station in Antarctica, these four stamps illustrate endangered whales. On the 2p stamp is a Sperm, unusual in that it has no whalebone with which to catch its food, but is a toothed whale with teeth in the lower jaw only - forty in all, each about 8 inches long. On the 8p stamp is a Fin. Often called the Ocean Greyhound, its is gracefully streamlined, very fast and reaches 80 feet in length. On the 11p stamp is the Humpback which reaches a length of 50 feet. On the 25p stamp is a Blue. The Blue can reach a length of 100 feet, but, due to intensive whaling, is rarely seen in the lengths over 80 feet. Whales are mammals. Dissection of a whale's flipper reveals the same (though modified) skeleton as the fore limb of a terrestrial ancestor.