Anatomy of Mystus seenghala m Digestive system

Toor, H. S.

Mystus seenghala (Sykes) is the most common catfish recorded from fresh water all over India. As it is purely a carnivorous fish, its alimentary canal is small and is very well suited for the animal diet. The mouth is large, with a longer upper jaw, and leads into a wide buccal cavity. Patches of backwardly directed teeth are present in the buccal cavity and pharynx. These teeth do not masticate the prey but are only meant for withholding it. Gill rakers are present and they also prevent the escape of the prey. Behind the pharynx the alimentary canal consists of the oesophagus, stomach (cardiac and pyloric), intestine (small and large) and the rectum. The rectum opens outside by the anus which is situated behind the pelvic fins in the mid-ventral line. Internally the alimentary canal presents a variety of patterns of mucous folds in different regions. Histological studies of the alimentary canal show that with the exception of the buccal cavity and pharynx, it consists of 4 layers, viz. serosa, muscularis, submucosa and mucosa from outside to inside. In the bucc al cavity and pharynx, however, the serosa is absent. Giant cells and lacteal spaces are present in mucosa and submucosa. The liver is bilobed with a pear -shaped greenish gallbladder. The bile duct opens into the anterior limb of the small intestine on a papilla. The pancreas is of diffused type.