In India and Nepal, the powdered horn of the black rhinoceros is regarded as a sure-fire aphrodisiac. It sells for a fancy price. In southeast Asia, the pulverized horn is sold as a cure for such ailments as malaria, insnity and toothache. In fact, the horn is so magical it can do almost anythig -- except keep the three-ton beast alive. Quite the reverse, in fact.

So to help African nations preserve their swindling herds, the Interior Department has placed the balck rhinoceros on the endangered species list.

The department estimates that there only about 14,000 left. Kenya's population has declined by 95 percent in the past decade. Tanzania's is down 70 percent, and there have been similar losses across sub-Saharan Africa.

The black rhino has two horns on its snout, a large one at the front and a small one just behind. And they are not, in fact, horns, but cone-shaped clusters of fibrous material. They are prized in Yemen as dagger handles, and the Mideast's new wealth is largely responsible for the animals' decline.

Until recently, only a few wealthy sheiks could afford a rhino-horn-handled dagger. But now Yemeni workers in Saudi Arabian oilfields earn such wages that almost any man can buy one. Thus, rhino horn that brought $12 a pound in 1969 now goes for $350 a pound.At that rate, an eight-pound horn will fetch $2,800. Currently, poaching is rampant, and, during the 1970's, some 8,000 horns were imported into North and South Yemen.