"I can undo a double sailor's knot under water," said Hervey. Tom laughed in spite of himself. "Hervey," said he, "do you know what kind of tracks those were you followed?" "A killyloo bird's?" "They were the tracks of a turtle and I was a fool not to know it. That turtle had the letters T. H. carved on his shell. Do you know what those letters might possibly stand for?" "Terrible Hustler?