Cape Cod Currency...The Provincetown Sand Dollars

If you have discovered a smooth, white sand dollar washed up on one of Cape Cod's beaches you have found a Cape Treasure! These creatures belong to the classification group Echinoderms, from the Greek words for Hedgehog and skin, meaning that they are spiney skinned. A sand dollar's velvety spines and tests (circular skeletons or shells) range in color from light brown to purplish brown while the animal is living. They whiten due to solar bleaching when they are dislodged from their sandy homes and are washed ashore. The Sand dollar's skeleton is made of calcareous plates with spines that are embedded in it's skin. These plates fuse to form it's protective shell. If you shake a sand dollar's test, you will hear it's "teeth" moving around inside, break it open and you will see the 5 bird shaped remnants. These are called "Aristotle's Lanterns" and are used to capture small worms and other food source organisms.

The sand dollar exhibits radial symmetry internally as well as externally, this refers to a spoke-like arrangement of parts around a central axis. The upper (aboral) surface has a star-like pattern of five petal shaped regions radiating from a central circular sieve plate (the madreprorite), which is the entrance to the locomotory vascular system. These petal shaped regions are perforated by the sand dollar's respiratory apparatus. The underside (oral surface) has five prominent channels (ambulacral grooves) emanating from the central mouth. These grooves join with similar but less prominent structures on the upper surface which pass mucus strings containing food toward the mouth. The sand dollar's anus is located on the edge of the test.

Sand dollars move by using a hydraulic tube foot system, similar to that used by Starfish. Water enters the aquatic vascular system through tiny pores in the sieve plate, goes through the canals and then enters a hollow contractile bulb at the end of each tube foot.

When the bulb contracts the tube lengthens, when it relaxes the tube is withdrawn. The ends of the tube feet are sucking disks and they coordinate to move the sand dollar along.

Sand dollars are either male or female; both eggs and sperm are expelled into the surrounding water through the five tiny openings around the sieve plate. After fertilization, the larvae develop into free swimming, ciliated, bilaterally symmetrical creatures. Roughly speaking, an object has bilateral symmetry if it can be divided into two halves, each the mirror image of the other. Several weeks later the sand dollars metamorphose into radically symmetrical adults and settle themselves into the ocean bottom, piling sand in front of themselves and then moving into it. Only a small percentage of these creatures survive, many of the larvae are lost, eaten, or settle into the wrong environment. Star fishes are one of the sand dollars' major predators, as are flounders, haddock, and cod.

How to Preserve and Harden a Sand Dollar

In order to achieve a white and clean looking specimen it is important to soak your sand dollar in fresh water first. Follow the steps below to preserve your live sand dollar.

1. As soon as possible after discovering your sand dollar soak it in fresh water. The water will discolor and begin to give off a foul oder so change it frequently until it stays fairly clear.
2. Soak your sand dollar in a solution of bleach and fresh water for 5-10 minutes
3. Remove from solution, rinse in freshwater and let dry.
4. Repeat steps 2 and 3 if needed, but remember each soaking in bleach weakens the sand dollar. Time in the sun will also whiten your sand dollar.

To harden sand dollars, mix together equal parts white glue and water and apply to both sides using a sponge brush.

Sand Dollar Cookies

Easy enough to make after a long day in the sun, this recipe makes four dozen crunchy treats that resemble sand dollars.

Sand Dollar Cookie Ingredients:

• 3/4 C butter
• 1 cup sugar
• 2 eggs
• 1/2 Teas. vanilla
• 2 1/2 C flour
• 1 Teas. baking powder
• 1 Teas. salt

Procedure:

1. Mix the butter, sugar, eggs, and vanilla thoroughly.
2. Add flour, baking powder and salt.
3. Mix and chill the dough for one hour.
4. Roll out the dough on a floured surface to 1/8"-1/4" thick.
5. Cut out cookies using a 3" cutter or water glass.
6. Place cookies on ungreased cookie sheet.
7. Draw a star in the center of each cookie with a dull knife.
8. Bake at 400 degrees for 7 mins.




Highland Light, Cranberries, Salt Water Taffy, Pilgrims Monument, Provincetown Sand Dollar, Provincetown Starfish