It is a reptile.

Oh, please send it away." "The Queen of the Island reprieves you," said he, and put down the terrapin, which went off very leisurely for a reprieved reptile.
Then Hazel produced a fine bream, which he had found struggling in a rock-pool, the tide having turned, and three sea crayfish, bigger than any lobster.

He chopped their heads off outside, and threw their tails into the pots; he stuck a piece of pointed wood through the bream, and gave it to Welch to toast; but Welch waved it aside.
"I see no cabbage," said he, grimly.
"Oh, I forgot.

But that is soon found," said Hazel.

"Here, give me the fish, and you take the saw, and examine the head of the palm-tree, which lies at Miss Rolleston's door.