In some species of fish the small intestine is in two to eight coils. The large intestines are short and straight, and the termination of the rectum opens into a cavity called the Cloaca. Labels: 1, Liver, 2, 3, Caecas or pouches connecting with small intestines. 4, 5, Small intestine, coiled. 6, Large intestine. 7, Biliary duct.