Family: echinoderm. Sand Dollars are the skeleton of several species of Sea Urchins that are native to Florida and other areas of the world. The common name, Sand Dollar, applies to members of the Clypeasteroida order in the sea urchin class and Echinoidea, of the echinoderm phylum. Sand dollars are common to the southeastern U.S., Australian and Caribbean seas and are usually found on sandy bottoms in shallow water. The typical shell is flat, circular and about 3 inches in diameter. The Sand Dollar digests food by engulfing sand and extracting tiny plants and animals. Interesting Facts: The Sand Dollar shares a unique relationship to Christians everywhere with its symbolic closeness to the birth and death of Jesus. This is told in the legend of the sand dollar.