Description: Hemitrochus varians (Menke, 1829) - apertural view of seagrape snail shell, 1.2 cm tall. The seagrape snail is a land snail (Pulmonata, Xanthonychidae), but dead shells do end up on marine beaches. Date: 5 March 2011, 00:33. Source: Hemitrochus varians (seagrape snail) (San Salvador Island, Bahamas) 2. Author: James St. John.