"Concentrate," hissed Zaphod, "on his name."
"What is it?" asked Arthur.
"Zaphod Beeblebrox the Fourth."
"What?"
"Zaphod Beeblebrox the Fourth. Concentrate!"
"The Fourth?"
"Yeah. Listen, I'm Zaphod Beeblebrox, my father was Zaphod Beeblebrox the Second, my grandfather Zaphod Beeblebrox the Third..."
"What?"
"There was an accident with a contraceptive and a time machine. Now concentrate."