What is the sand dollar?

The sand dollar is a maritime animal named after its liberated round shape that resembles a large coin. This type of animal belongs to the animal class known as echinoids and are close to relatives of the sea hedgehog and starfish. Many people are familiar with sand dollars that have washed up on the beach and the sun ran to a light sandy color. However, when this animal is alive, it has a darker color and covered with small mobile spines. When it is alive, rows of small tubular legs spread on the pores. These respiratory stems or stages function as gills by rinse water over the sand dollar to keep it oxygenated. Small spines covering their exoskeletons are covered with slight hairs or cilia . On the underside of the animal, these spines and hair are transmitted by food particles along the grooved lines in hard skin that leads to the central opening where the mouth is located. The spine and hair also help in moving along the seabed.

A small circular opening on the underside of the sand dollar seems sufficient for the mouth, but this animal has teeth. If you shake the bleached skeleton of the sand dollar (called the test ), you will probably hear something that is rattling inside. Open the test and find a few small white pieces that served as teeth.

sand dollars usually occur in large groups and have limited enemies due to the hard outer shell along with a negligible internal meat. Some predators of these animals include starfish, snails and some fish. The animal gives birth to the larvae through the upper pores of the exoskeleton. Young people are a mile have developed along the ocean streams, and those who survive go through many stages before the development of the outer shell of an adult sand dollar with an external calcium.

sand dollars are found in coastal waters around the world. People often gather them for their beauty and creepPky also commonly found in decorative art with the theme of the sea.