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 The majority of gastropods have a single, usually spirally, coiled shell into which the body can be withdrawn.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 aches can be caused by various causes such as constipation, indigestion, ulcers, food poisoning, inflammation of the gall bladder, kidney stones, liver disease, pancreatitis, urinary tract infections and gas. Ulcers in particular, are the result of damage to the mucous membrane of the stomach.