Possible Clues:

• And thereby hangs a tail? Never
• Thereby hangs no tale, by the sound of them
• And thereby hangs a tale? Not, by the sound of it, from them
• Thereby hangs a tale? By the sound of it, never
• No need for beastly detailing when there's one fellow over ten more
• Seems there are about ten such toms, yet there's no end of them