The 140 antiquities stolen on Christmas Eve from Mexico City's National Museum of Anthropology may be on their way to some hidden treasure vault -- the type beloved of suspense novelists, where a wealthy collector keeps them for his own pleasure, speculated an expert in pre-Columbian art.

The objects, comparable in value to some of the King Tut tomb finds in Egypt, are priceless, said Gordon McEwan, Dumbarton Oaks pre-Columbian assistant curator.

"Any legitimate collector or organization would know immediately what they are, and wouldn't purchase them," McEwan said yesterday. "Mexican antiquities have no peer. And these are among the best they had."

McEwan also said, "Secret collections are out there. A great number are illegally exported. Every so often a superb piece that no one has ever seen will surface. You hear tales of objects kept for 20 years and then marketed."

A comprehensive list is on its way around the world today. The precious tiny antiquities are made of gold, jade and obsidian, and the size of many of them explains the ease with which the thieves were able to transport the ancient artworks. The museum's stone statues, which weigh many tons, were undisturbed.

Descriptions of the objects, warnings that they could be tucked into suitcases or even smaller containers, have gone out to several hundred customs offices, police stations, land and air ports along the Mexican and Canadian borders, according to Russ Parry, assistant chief for the aliens and fugitives unit at the International Criminal Police Organization (Interpol) bureau here. Pictures of the objects are being sent out by express mail.

Dr. Hugo Gutierrez-Vega, cultural minister of the Mexican Embassy here, released a list of the objects late yesterday.

Among the more important pieces:

*A Zapotec mosaic "bat" god (Murcielago) mask, 11 1/8 inches long, made of pieces of blue-green jade with eyes and teeth of white shell. The mask was found with masses of beads in a Monte Alban tomb Stage II (circa 100 B.C.-A.D. 200). The Zapotec and the Mixtec people lived in the Valley of Oaxaca.

*A Mixtec pectoral (breastplate), 3 1/8 inches by 3 1/8 inches, circa 1300-1521 from Yanhuitlan. This is a round gold shield with four arrows on each side and 11 gold beads hanging from it. Its center is a gold step fret interlocking with a turquoise mosaic. A replica was once presented to the queen of England.

*A jade-and-shell mask of a dignitary, 11 7/8 inches high, from the Classic Maya Culture, circa 692. This was found in the crypt of the Temple of the Inscriptions in Palenque, Chiapas. The mask comes from the only unviolated tomb of an important official yet found. The mask covered his skull. His skeleton was attended by those of six murdered slaves.

Many of the pieces are gold -- rare objects that escaped the European conquerors who melted down much of the fabulous art of Mexico. A disk-shaped gold sheet 15 centimeters in diameter is one of the larger pieces. A gold pectoral with a solar disk depicts a sun god. Two laminated gold masks are just three centimeters in diameter. Five gold pendants have ornaments of turtles, bells or skulls. Two gold arrows are each only two-thirds of a centimeter in diameter.

Some, Gutierrez-Vega said, are actually fragments. Still, they are valuable for their craftsmanship, their antiquity and their precious material.

McEwan called the objects "extraordinary, unique." He said that the 630 objects in the Dumbarton Oaks pre-Columbian gallery in Washington are in the same class.