The digestive tract of the mollusca phylum is complete with a mouth, anus and complex stomach. The mollusks diet dictates the pattern of the stomach. Food is taken up by cells lining the digestive glands. Undigested materials are compressed and packaged, then they are excreted through the anus.
Clams
Food particles and water enter the mantle cavity, an opening between the two valves. Secretions cause smaller particles to adhere to the gills, and cilia action moves the particles toward the mouth. The digestive system includes a mouth, a stomach, and an intestine. The anus empties the waste.
Snails
Snail have sets of jaws inside their mouths used to cut off bits of food. The radula, "snail tongue", moves back and forth very rapidly to grind up pieces of food. It wears away with use, but it is continuously replaced. The teeth are fastened to the radula in rows. Snails may have up to thousands of individual teeth, with tiny cutting points called cusps. The food moves to a dilated stomach, which is followed by the long intestine, whose end is dilated to form the rectum. The anus opens into the mantle cavity near the edge of the mantle and the shell.
Octopuses
The digestive system starts when the octopus gets a hold on its prey and squeezes with great force to kill it. The octopus sucks on the prey with its beak and lips. It flows down the esophagus through the crop and into a digestive gland. The food flows into the stomach through a small intestine and is excreted out the anus.