"Earthman, the planet you lived on was commissioned, paid for, and run by mice. It was destroyed five minutes before the completion of the purpose for which it was built, and we've got to build another one."

Only one word registered with Arthur.

"Mice?" he said.

"Indeed Earthman."

"Look, sorry - are we talking about the little white furry things with the cheese fixation and women standing on tables screaming in early sixties sit coms?"

Slartibartfast coughed politely.

"Earthman," he said, "it is sometimes hard to follow your mode of speech. Remember I have been asleep inside this planet of Magrathea for five million years and know little of these early sixties sit coms of which you speak. These creatures you call mice, you see, they are not quite as they appear. They are merely the protrusion into our dimension of vast hyperintelligent pan- dimensional beings. The whole business with the cheese and the squeaking is just a front."

The case for interbreeding is getting weaker all the time, says David Serre at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. "All the information we have from different sources points in the same direction.")