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 The majority of gastropods have a single, usually spirally, coiled shell into which the body can be withdrawn.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.
Digestive tract causes of stomach problems. Stomach problems may be caused by conditions of the digestive tract including: Bacterial, parasitic or viral infection of the gastrointestinal tract. Celiac disease (severe sensitivity to gluten from wheat and other grains that causes intestinal damage). Diverticulitis (inflammation of an abnormal pocket in the colon).