so many sand dollars not a lot of time

One of my favorite spots for finding sea shells and sand dollars was Santa Maria. There weren't many big shells, but the ones that I saw were beautiful. We saw lots of sand dollars, huge ones that were the size of my hand. The sand dollars were scatered every where on the beach. We found a few live ones and there were a lot of the dead ones.

Can you tell which sand dollar is still alive? It's the black one. 

This sand dollar is still alive......we threw it back into the ocean