Question

The intestine of dog fish is characterized by the presence of:

• A. Pyloric valve
• B. Scroll valve
• C. Cardiac valve
• D. Sphincter of oddi

Answer 1

The correct option is B Scroll valve

In Scoliodon, the mucus lining of the intestine becomes folded anticlockwise into a longitudinal spiral or scroll of about two and a half turns. This is called the scroll valve or spiral valve. It serves to delay the passage of food and offers an increased surface for absorption like the typhlosole of an earthworm. Hence, option B is the correct answer.