Thanks for your interest!
“When we were little,” the Mock Turtle went on at last, more calmly, though still sobbing a little now and then, “we went to school in the sea. 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!”