a large reptile(爬行动物) which has a thick shell covering its body. a hard substance formed from the skeletons(骨骼，骨干) of very small sea animals. It is often used to make jewelry. a very large mammal with the general shape of a fish and one or two blowholes for breathing. 4. A type of small fish which appears to swim in an upright position and whose head looks a little like the head of horse.

Guessing game: What are they?

turtle

coral

whale

sea horse