Snails and Slugs: Phylum Mollusca, Class Gastropoda. The Class Gastropoda (in Phylum Mollusca) includes the groups pertaining to snails and slugs. The majority of gastropods have a single, usually spirally, coiled shell into which the body can be withdrawn. The shell of these creatures is often what is recovered in a fossil dig.
Causes of bleeding in the stomach can include: 1  Ulcers: Ulcers may enlarge and erode through a blood vessel, causing bleeding. 2  Gastritis. 3  Cancer. Gastric varices.  Dieulafoy 1  lesions. Portal gastropathy.
Weakness in your stomach lining allows digestive juices to damage and inflame it, causing gastritis. Having a thin or damaged stomach lining raises your risk for gastritis. A gastrointestinal bacterial infection can also cause gastritis. The most common bacterial infection that causes it is Helicobacter pylori. Itâs a bacterium that infects the lining of the stomach. The infection is usually passed from person to person, but can also be transmitted through contaminated food or water.