Anatomy of finfish and shellfish

Unit 4 - Gastro Intestinal Tract OR Digestive system and associated digestive glands

4.1.6. Anus
It is the posterior opening of the alimentary canal or digestive system. The internal surface of the region near the rectum is covered with an epithelium rich mucous cells. The anus is made up of an inner circular and outer longitudinal muscle layer. The circular muscle is thick developed forming sphincter. The region of anus facing the anterior has the epithelium continues with the skin.