Answer:
Blue crabs have three pairs of walking legs and paddle-shaped rear swimming legs. Males have a strongly tapered abdomen, or "apron," that resembles an inverted T, mature females have a broad, rounded abdomen, and immature females have a triangular abdomen
The outside of these corals have a wrinkled appearance. Horn Coral grows in a long cone shape like a bull's horn. The fossil is the skeleton of the coral animal or polyp. They built these cone shaped structures from calcium carbonate that came from the ocean water.