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 The majority of gastropods have a single, usually spirally, coiled shell into which the body can be withdrawn.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.
Bloating and Upset Stomach. Gas has buoyancy and gas pockets can become trapped in the upper and lower intestines. The gas acts like a cork, impeding or halting the flow of gastric juices and causing pressure to be built up. This pressure causes painful bloating and swelling of the abdomen. When gas pockets form in the stomach, this can cause the stomach to distend, causing discomfort or pain.