"I knew you were a hardhead," said Gunn. "That's why I left the most interesting part till last." He paused and removed his glasses and rubbed the lenses with a piece of Kleenex. Then he replaced the black rims over his hawkish nose. He continued speaking as if lost in a dream. "During the Triassic Period in geological time, and before the Himalayas and the Alps rose, a great sea swept over what is now Tibet and India. It also extended over Central Europe and ended in the North Sea. Geologists call this once-great body of water the Sea of Tethys. All that remains of it today is the Black, the Caspian and the Mediterranean Seas."

"You'll have to pardon my ignorance of geological time eras," Pitt interrupted, "but when did the Triassic Period take place?"

"Between one hundred eighty and two hundred thirty million years ago," replied Gunn. "During this time an important evolutionary advance occurred in the vertebrate animals as the reptiles demonstrated a great leap over their more primitive ancestors. Some of the marine reptiles attained a length of twenty-three feet and were very tough customers. The most noteworthy event was the introduction of the first true dinosaurs, who even learned to walk on their hind legs and use their tails for a kind of cane."

Pitt leaned back and stretched his legs. "I thought that the era of the dinosaurs occurred much later."

Gunn laughed. "You've seen too many old movies. You're undoubtedly thinking of the behemoths that were always portrayed in the early science fiction films, menacing a tribe of hairy cavemen. They never failed to have a forty-ton Brontosaurus or a ferocious Tyrannosaurus or a flying Pteranodon chasing a half-nude, big-titted heroine through a primeval jungle. Actually these more commonly known dinosaurs roamed the earth and became extinct sixty million years before man appeared."

"Where does your freak fish fit into the picture?"