The master was an old Turtle--we used to call him Tortoise--'
Why did you call him Tortoise, if he wasn't one?' Alice asked.
We called him Tortoise because he taught us,' said the Mock Turtle angrily; 'really you are very dull!'
You ought to be ashamed of yourself for asking such a simple question,' added the Gryphon; and then they both sat silent and looked at poor Alice, who felt ready to sink into the earth.

Author: Lewis Carroll