The Digestive System of a Sand Dollar (Clypeaster subdepressus)
The sand dollar has a complete digestive system. It's mouth is on the underside of its body and its anus is on the topside. It is a deposit feeder ingesting sand and water and sifting out food particles. It uses the cilia on its underside to direct the sand mixture into its mouth. The mouth has a jaw with five teeth like sections to grind food. They may chew for 15 minutes. A sand dollar's digestion is a slow process, sometimes taking up to two days to fully digest its food. Once the food is in its mouth it goes into the esophagus, which is made up of two parts, the upper and lower. The upper esophagus is a tube which contracts to transport the food to the lower esophagus. The contractions of the lower esophagus pushes the food into the stomach. The digestive enzymes in the stomach break down the nutrients so they can be absorbed into the sand dollar's body. The waste passes into the intestine and is excreted through the anus.
The sand dollar has a complete digestive system. It's mouth is on the underside of its body and its anus is on the topside. It is a deposit feeder ingesting sand and water and sifting out food particles. It uses the cilia on its underside to direct the sand mixture into its mouth. The mouth has a jaw with five teeth like sections to grind food. They may chew for 15 minutes. A sand dollar's digestion is a slow process, sometimes taking up to two days to fully digest its food. Once the food is in its mouth it goes into the esophagus, which is made up of two parts, the upper and lower. The upper esophagus is a tube which contracts to transport the food to the lower esophagus. The contractions of the lower esophagus pushes the food into the stomach. The digestive enzymes in the stomach break down the nutrients so they can be absorbed into the sand dollar's body. The waste passes into the intestine and is excreted through the anus.