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 The majority of gastropods have a single, usually spirally, coiled shell into which the body can be withdrawn.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.
The full list of all possible causes for Upset stomach described in various sources is as follows: Alcohol excess Barbiturate abuse - upset stomach Food poisoning; Gastritis; Gastroenteritis; more causes...Â» See full list of possible disease causes of Upset stomach. Drug side effect causes of Upset stomach The following drugs, medications, substances or toxins may possibly cause Upset stomach as a side effect. Zonisamide