Labrador to N.J. Mostly subtidal to more than ½ mile (792m) deep on sand bottoms, but also in lower intertidal zone (especially northward) in bays and on ocean beaches.

Cape Cod is a popular spot for finding “true” Sand Dollars. Their range, however, is from Labrador to Maryland. As it was said before, most people refer Keyhole Urchin as Sand dollars. Keyhole Urchins have keyhole – shaped holes in their shell, or test. Common Sand Dollars are circular and have a design resembling a spoke – like arrangement of five petals similar to Keyhole Urchins.

Common Sand Dollars also have fine velvety spines covering their shell. However, do not have holes through their shells.

Remarks:

Sand Dollars shuffle through loose sand, feeding on diatoms and other microorganisms.

Flounders and other bottom fishes, in turn, feed on them.

Color highly soluble, stains indelibly.

Sometimes called Sea Biscuits, are flattened relatives of the Se Urchins with the movable spines greatly reduced in size.

The animals live in deeper water, half – buried in sand,

Feeding on organic material and plankton. Cilia on the spines move these food particles until they are trapped by mucus around the spines and are pushed into the animal’s mouth.

A large pacific starfish feeds on Sand Dollars. Sand Dollars and Sea Urchin “skeletons” are found washed up on beaches.

The skeleton of a Sand Dollar

The skeleton of the Sand Dollar consist of close – fitting calcareous plates forming a rigid test; body globular to dislike, covered with fine to coarse, movable spines. Typical 5- part plan sometimes modified towards bilateral symmetry with obvious front – rear, left- right organization. Tube feet in bands, protruding through tiny pores; pore patter useful in identification.

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To clean sand dollar and keyhole urchins, soak them in a solution of bleach (50%) and water (50%) until they turn white. If necessary, gently scrub the test with a soft toothbrush. Do not leave them in the bleach solution any longer than necessary. if they are left in the solution too long, they will become even more fragile. After the bleaching process is completed, rinse the sand dollars and Keyhole Urchins in fresh water and put them on paper towels in the sun to dry. To make Keyhole Urchins more durable, paint them with a coat of water base white glue. The glue soaks into it and dries hard and clear. There is a similar “sand dollar hardener” product sometimes available in variety stores and craft shops.

Many uses of Sand dollar and Keyhole Urchins

Searching and finding them is the exciting and fun part of shelling.

When the animal dies and the shells become empty, they turn into prized gifts for making – gifts to search for, contemplated, and shared with others.

Using as amulet and ornament

Through the ages, the Sand Dollar has been used as both ornament and amulet. In some quarters it is known as the Holy Ghost shell because the markings on the shell seem to symbolize the birth, crucifixion, and resurrection of Christ. The five pointed star on the underside of the sand Dollar is thought to represent the star of Bethlehem, and also resembles the outline of an Easter Lily. The narrow elliptical openings are reminiscent of the five wounds made in the body of Christ during crucifixion. On the underside of the shell id an easily recognize outline like that of the Christmas poinsettia. When the shell broken open, cells are found, each holding five objects that look like five birds in flight. These can represent the doves of peace. Another interpretation of these birdlike objects connects them to the angels who sang to the shepherds on the Christmas morning.

Note: If you are interested in taking edible shellfish, be advised town licenses are required. Regulations and fees vary from town to town.

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Proper handling this kind of shells must begin the moment you pick them up off the sand or scoop them out of the water. This is especially important with fragile shells such as Keyhole Urchins. They may not make a trip safely off the beach unless you handle them with care and transport them properly.

Patience and sharp eye are required for discovering urchins uncovered by the gentle back and forth movement of the water as small waves break onto shore. In drier sand, keen observation will enable you to see the center of the urchin crowning the surface. Very carefully scrape the sand out from around the urchin. Gently dig under the sand and the urchin up together. Urchins are fragile, so do this slowly. Once it is out of the sand, wash it off and admire your beautiful find.

Transporting

The best method for carrying urchins safely is to stack them flat in a plastic pail. Be careful not to place Keystone Urchins and other shells together or otherwise it brake.

Once off the beach and back to your location, let them dry and then repack them for transport home. Take the time to wrap them in tissue paper or paper towels. Then carefully layer them in an empty tissue box or small plastic container. This will help protect them from breaking.

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Keyhole Urchin, Mellita quinquiesperforata has 5 slitlike holes; in life light – to golden – brown tinged with green; tests bleach whitish. To 3”in. (75mm) or more.

Keyhole Urchin

Is one of the most commonly and enjoyable shells to find on Honeymoon Island.
Keyhole Urchin more commonly called a sand dollar. The term sand dollar is generally used to describe all varieties of flat circular sea urchins. A keyhole Urchin is identified by the Keyhole – shaped holes in its body. The Keyhole Urchin commonly found in this place range from silver dollar size to about six inches in diameter, with the majority being three to five inches.

Keyhole Urchin , like other sea urchins, are bottom dwellers unable to swim. These animals live just under surface of the sand. they use hundreds of minute tube – like feet or velvety fine spines on their underside to move along the sandy ocean or bay floor. Keyhole Urchins are disk – shaped, of radial symmetry having a spoke – like arrangement of five petals – like designs radiating from a central point. These animals’ skeletons, called tests, act as protective shell. When they are alive, Keyhole Urchins have a greenish spiny skin. When they die the spines fall off, the shells wash around in the surf, and they are then bleached white by the sun.

When searching for sea shells; keyhole Urchins – sand dollar found on the beach are generally smaller than those found on the sandbar and many have been bleached white by the sun.

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A flat echinoid; test almost round with a 5 petaled pattern of tiny holes; bleaches white. In life with a feltlike coating of fine spines; brownish, tinted purple to red; sometimes distinctly patterned with dark petals and large marginal spots.To3”in. (75mm) diameter.

Sand Dollar

Sand Dollars are beautiful animals. They are flat and round like a cookie, with a five – point star designed on top. Living sand dollars are covered with short spines. If you pick up a sand dollar and turn it upside down, you will see a small hole in the center. That is its mouth. Sand dollars may be found in tide pools or on the beach.

The common sand dollar has a fancy design on top. All lines and shapes in the design are in groups of five. Looks for ten rows (five pairs) of ovals shaped like kernel of corn. There are five “kernels” in each row. In between each pair of kernel rows is a pair of triangles.

The Keyhole Urchin is a kind of sand dollar. It is large and not as perfectly round as the common Sand Dollar. Young Keyhole Urchins have five long, narrow slots in their bodies. Each slot is shaped like the keyhole of a door, which is how this animal got its name. The slots gradually fill in as the animal grows.

Common Sand Dollar
Northern Canada to Maryland
Color: Light brown
Size: 3 inches across

Keyhole Urchin
Cape Cod, Massachusetts, to Florida
Color: tan or gray
Size: 5 ½ inches across

“Sand dollars loses their spine after they die. This shel is fragile, so carry it carefully”

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The Echinodermats have skeletons constructed of calcareous plates with spines that are more or less embedded in the skin: in sea cucumbers, these plates are loosely scattered, and the body is flexible; in sea stars and brittle stars, the plates articulate and the skeleton is somewhat pliable ;whereas in sea urchins and sand dollars, the plates are fused and sutured together, forming a boxlike, immovable protective shell or test.

One of the most distinctive characteristics of echinoderms is that all have radial symmetry (a spokelike arrangement of parts around a central axis, as in jellyfish, anemones, etc.), compared with the bilateral type of symmetry (the individual can be divided into equal and opposite right and left halves), Commonly encountered in other metazoans , including our selves. This design is especially clear in sand dollars, where the upper (aboral) surface has a starlike pattern of five petals – like figures radiating from a central disk – shaped sieve plate (madreporite), the entrance to the unique locomotory vascular system. These petals – shaped regions on the aboral surface are the areas perforated by the animal’s respiratory apparatus. The underside (oral surface) has five relatively prominent, equidistant channels (the ambulacral grooves) emanating from the central mouth. These grooves unite with similar, less clearly defined structures on the upper surface and pass strings of mucus containing food particles toward the mouth.

The anal opening is at the edge of the test.

The Northern Sand Dollar, Echinarachnius parma, ranging from mean low water to about eighty fathoms, from Long Island Sound northward, is about three inches in diameter and has no openings in its test, whereas the slightly large Southern Sand Dollar, Keyhole–urchin, Mellita quinquiesperforata,
Which is normally found from Cape Hatteras to the West Indies, but occasionally strays as far north as Martha’s Vineyard, has its skeleton pierced by five elongate, regularly spaced holes. The genus Mellita was originally described by the great naturalist, Louis Agassiz.

Living sand dollars are often abundant on sand bottoms. Their tests are coated with large numbers of velvety fine spines that contrast with the long, sturdy, pointed spines of the closely related purple and green sea urchins. Both the tests and the spines vary from uniform light brown to purplish brown.
Sand dollars live just beneath the surface of the sand when exposed, they bury themselves by piling sand in front of them and moving into it. When they die and are washed up on the beach, the spines fall off and the tests eventually bleach and become white. A test from a dead dollar, when we pick it up and shake it, rattles because of the now loosened and dried complicated dentary apparatus, called the Aristotle’s Lantern because of its imagined resemblance to an old Greek oil lamp. Aristotle’s Lantern in the living animal is an intricate and beautiful structure of five groups of calcareous plates bound by muscles from which five calcium carbonate teeth project to the outside. The teeth are used in capturing the small worms and other organisms on which these animals live.

Sand dollar move by the hydraulic tube-foot system, like the method used by starfish and sea urchins. They manage locomotion by coordinated movements of the spines. In this system, water enters the water – vascular system through minute pores in the sieve plate, goes through canals, and finally enters a hollow contractile bulb at the inner end of each tube foot.

When the bulb contracts the tube lengthens, and when it is relaxed the tube is withdrawn. The ends of the tube feet are sucking disks. The tube feet coordinate to pull the animal along.

7 cm (approx. 2 ¾”)

Sand Dollars – (a) Mellita quinquiesperforata – The Keyhole – Urchin, common in shallow southern Atlantic waters. Upper side.

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As well as a dense covering of spines, sand dollars bear many tubefeet and pedicellariae. The latter remind one of long-handled secateurs used for pruning trees; there are pair of toothed pincers on a long rod which can bend on its base. One function of the pedicellariae is to prevent animais such as barnacles from settling on the sand dollar and they may even secrete a poison. The pedicellariae and the spines appear to be little protection against marine snails and starfish, the former being able to rasp holes in the test with the radula, and so here the sand dollar rely on burrowing for safety. When a starfish passes through a bed of sand dollar it leaves a clear track about 4 ft wide where the sand dollars have hastily buried themselves. A sand dollar takes 1- 3 minutes to bury itself, but luckily for the sand dollar a starfish does not move very fast.

The appearance of a starfish that does not eat sand dollars causes no such alarm, so it is likely that sand dollars can recognize dangerous starfish, probably by chemicals from their bodies. They are not the only animals to do this, the Antarctic limpet Patinigra Antarctica,for example,”flees” from limpet – eating starfish but ignores other species. If their flight is so successful one wonders how starfish ever get a meal.

This is one more example to support the idea that, generally speaking, predators take only weakly, ailing or infirm prey. The others are usually able to get away.

Apparently, starfishes are one of the main enemies of Sand Dollars. When a starfish crosses a bed of Sand Dollars, the dollars down current from the starfish quickly bury themselves. Flounders, cod, and haddock feed extensively on sand dollars when they can.

The sand dollar “Clypeaster subdepressus has an unmistakable flat shape and a striking pattern of five petal – shaped marks. This species range from North Carolina to Brazil.

Phylum – Echinodermata
Class – Echinoidea
Order – Clypeasteroida
Genera & species – Clypeaster rosaceus, West Indian sea biscuit, Mellita sexiesperforata, Keyhole sand dollar, Rotula orbiiculus, Scutellid sand dollar, and Others.

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In Sand Dollars, the sexes are separate; eggs and sperm are spawned directly into the surrounding water through the five small openings around the sieve plate. After fertilization, the larvae develop into free – swimming, planktonic, ciliated, bilaterally symmetrical individuals, and several weeks later they metamorphose into radially symmetrical adults and settle to the bottom. This metamorphosis is one of the most remarkable in the animal kingdom. Only small percentages survive, for most of the larvae are lost, are eaten, or settle in the wrong environment. The eggs of sand dollars have been a favorite tool of experimental embryologists since the first decades of this century. They are relatively plentiful, hardy, and easy to culture in the laboratory and their habits of growth and development are simple to observe.

Sand dollars release eggs and sperms into the sea where fertilization takes place.

After swimming freely for some time the larvae undergo radical changes and settle on the sea bed as young sand dollars.

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Sand dollars are found on sand shores and tidal flats where they are not exposed to surf. Only in the quietest places can they be found above the low tide mark, hiding themselves under the sand. They are often very abundant and as many as 468 have been found in 1sq yd. They dig themselves just under the surface of the sand by ploughing down at a shallow angle, propelled by the combined movement of the spines. Sand gets piled up in front and covers them. Some species submerge completely, although their outline can be made out, while others leave the rear end exposed. When covered with water sand dollars stand on edge with one third of the body buried. They orientate themselves so that the body is held at right angles to the flow of water.

Continuous feeding

The spine of a sand dollar are covered with cilia whose beating sets up minute eddy currents that draw in tiny organisms and particles from the water or sand surrounding the sand dollar. These organisms are trapped in mucus secreted by the spines. The mucus flows down the spines and is gradually passed down branched pathways on the surface of the sand dollar, accumulating as it goes into five large tracts which lead around the edge of test and along the underside to the mouth at the centre. Examination of the test shows these tracts as fine grooves with even finer branches. This selective method of feeding differs from that of many sand- dwelling animals which eat, and void, large amounts of sand and extra edible material as passes through the gut.

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Family: (Echinarachnius Parma)

The flat, thin, nearly circular skeletons of a curious group of echinoderms that we sometimes encounter between tidelines on the outer marine beaches are commonly known as sand dollars. The name was acquired because of their fancied resemblance to that now rare American coin, the silver dollar. They belong to the phylum Echinodermata, from the Greek words for hedgehog and skin, indicating that these are “spiny- skinned” animals. This division of animals contains the closely related sea stars, brittle stars, sea urchins, sea cucumbers, and the ancient sea lilies.

Sand dollar, also known as cake urchins or sea biscuits, are closely related to sea urchins. Although flat rather than spherical, their shells, or tests, show the basic 5- armed body pattern of echinoderms such as starfish, brittlestars and basket stars.

In the centre of the upper surface of the test a “star” of pinholes can be seen but, compared with the other echinoderms mentioned, sand dollars are bilaterally symmetrical. The tests of some sand dollars also have characteristic slits around the edges giving them the name of “keyhole urchin”. A flat test is not as strong a shape as the globe tests of the sea urchins and the tests of sand dollar are strengthened inside by supporting pillars between the upper and lower surfaces.

The test is 3 – 4 in. across and is purple or black. IN some places it is ground up to make an indelible ink.

In the water – worn test is all that is usually seen of a sand dollar as in life it generally lives buried in sand or mud below the low tide mark. The intact animal is covered with short spines, about 1/16 in. long, which give it the appearance and feel of velvet, very different from the long sharp spines of sea urchins. Unlike sea urchins and starfish there is a definite “forward end to a sand dollar and the anus is at the rear edge instead of the centre of the upper side.

Sand dollars are found mainly in the warm waters of the world and most species live on the shores of America and Japan, but one is Known from as far north as Alaska.

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