The sand dollar has a hard shell that is purple when it is alive. Sand dollars have tube feet and spiny skins. They are invertebrates having a flat, circular outer shell. The common sand dollar of the notheastern United States is found on sandy bottoms in comparatively shallow water. The entire shell is penetrated by many small, brown spines that give the shell a velvety appearance and enable the animal to move about.
Sand dollars obtain food by engulfing sand from which they extract minute plants and animals.
Sea Horse A seahorse is a very strange type of fish. It swims along in an upright position, holding its long-nosed head up. That is why it is called a sea horse. It does not wave its tail, but moves the fin on its back. The long tail can be curled around seaweed and use it for an anchor The male seahorse has a special pouch for carrying eggs that have been laid by the female.