RIYADH, Saudi Arabia (AP) _ Clad in traditional Arabian robes and headdress, Dr. Lawrence Curtis sits in his study, surrounded by the things he loves - an extensive zoological library, three snakes and a scorpion that paces in a small box.

Every so often, a curious ostrich peers through the window.

Home for Curtis is Riyadh's zoo.

The 58-year-old Texan was hired specially to establish a zoo in this oil- rich nation and sometime in the future, he said, ''Saudi Arabia may be breeding more endangered species than many advanced countries.''

Curtis spent 15 years as a zoo director in Fort Worth, Texas, and another 15 in Oklahoma City.

''I was bored with conventional zoos,'' he said, and 18 months ago heard that Riyadh was planning to open a zoo and needed a director. He packed enough clothes for two weeks and headed for the Saudi capital.

He was hired on the spot and given just four months to prepare for the zoo's opening in March 1987.

Today, the Riyadh zoo is home to 1,200 animals, many of them endangered species. It is also an oasis, carpeted in lush grass and filled with flower beds, bubbling man-made streams, small trees, and flowering vines thriving in the highly irrigated desert soil.

Nearly 7,000 visitors a day pass through its gates - men on Mondays, Wednesdays and Fridays and veiled women on Tuesdays, Thursdays and Sundays, in accordance with Saudi Arabia's Islamic tradition of separating the sexes.

To Riyadh's residents, the zoo is a welcome change of scenery. To Curtis, the zoo is much more.

''I really wanted our zoo to have an international reputation for conservation,'' he said.

One of his first tasks was to help persuade the municipality to issue a policy statement supporting the Convention of International Trade in Endangered Species (CITES), a treaty designed to protect wild animals in their native countries.

Saudi Arabia supports the treaty although it has yet to sign it - a point Curtis thinks will change soon - but the expression of support made it easy for him to get colleagues all over the world to help stock the zoo.

In keeping with CITES guidelines, no endangered species were collected from the wild.

An Arabian leopard and an ibex were shipped from Cincinnati's zoo. Pigmy hippos came from the Bronx Zoo in New York City. Boston sent antelopes. Miami, Cleveland and Duke University sent lemurs. San Diego contributed a scimiter horned oryx, and a golden lion marmoset came from Washington, D.C.

The zoo in Cairo, Egypt, sent giant tortoises, the Singapore zoo a crocodile, the Sydney zoo in Australia a kangaroo and two tapirs arrived from the zoo in Lima, Peru.

Bedouins, the nomads who live in Saudi Arabia's desert, brought in lizards, a caracal and a hyena in the back of pick-up trucks. And so it went, until the zoo's eclectic collection rivaled those of its more established counterparts.

''We've got an Indian mynah who speaks Arabic, and a parrot who speaks Swahili,'' said Curtis. ''He's next to a macaw from Brazil and you know what they speak there (Portuguese). We really have a multilingual zoo; it's like the United Nations.''

Getting the animals to Riyadh was only half the chore.

''The big challenge was acclimatization,'' Curtis said. ''We had to make a lot of modifications.'' Upon his arrival, he was given a list of animals approved for acquisition but he rejected some as inappropriate.

A wild horse was scratched for want of adequate running space, and several poisonous snakes were eliminated due to lack of staff expertise in handling them. Many animals need special care in order to thrive in Riyadh's desert climate.

''The key to acclimatization is spraying and misting systems, so we installed a lot of that,'' Curtis said. The zoo also invested in shade cloth, which cuts out 80 percent of sunlight in the summer months, when temperatures often reach 122 degrees.

Reptiles accustomed to high humidity are sprayed with water.

Like his charges, Curtis seems to have adapted to his new environment. He wears the local robes and headdress, known as a thobe and ghutra.

He takes frequent desert trips to study and photograph Saudi Arabia's native fauna.

''This country has made remarkable progress. It has a big commitment to conservation,'' Curtis said. ''They've already created national parks, there's an endangered species list, and we've got endangered species legislation coming up.''