The inside surface area is shaped in a crescent. It consists of a spiral valve which is made up of the small intestine. Although the dogfish shark has a relatively short small intestine compared to other animals, therefore, the spiral valve allows for a more compact form of the small intestine.
Hence, this structure provides maximum surface area over a relatively short distance in order to make the absorption of nutrients efficient achieved from the food, the sharks had from eating different sea animals.
Hence, this structure provides maximum surface area over a relatively short distance in order to make the absorption of nutrients efficient achieved from the food, the sharks had from eating different sea animals.