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 The majority of gastropods have a single, usually spirally, coiled shell into which the body can be withdrawn.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.
Stomach and duodenal ulcers are usually due to one of two causes: the bacterium Helicobacter pylori or nonsteroidal anti â inflammatory drugs (NSAIDs) like aspirin, ibuprofen, and naproxen. An ulcer, regardless of the cause, can cause abdominal pain, bleeding, or even cause a hole (perforation). An ulcer is maintained by an acid environment in the stomach and pepsin, which is produced in the stomach. Chronic infection with H. pylori causes an increase in acid.