Morpho-histology of the alimentary canal of an Indian fresh-water perch, Colisa fasciata (Bloch) in relation to food and feeding habits.

The morpho-histology of the alimentary canal in an Indian freshwater perch, Colisa fasciata (Bloch) in relation to food and feeding habits has been described. C. fasciata is an omnivorous, mid-feeder. The mouth is protractile. The alimentary canal comprises the lip, buccal cavity, pharynx, oesophagus, stomach, pyloric caeca, a long and coiled intestine and the rectum. The teeth on the roof and floor of the buccal cavity, jaw teeth, pharyngeal teeth and horny pad teeth are all adapted to the nature of the food ingested. The nature and disposition of taste-buds and mucous cells on the lips suggests that the fish is a taste-feeder. The presence of taste-buds in the anterior oesophagus indicates that the gustatory sense extends upto the oesophagus. The stomach is divided into the cardiac and pyloric regions. The surface epithelium of the cardiac stomach secretes mucous and the glandular epithelium contains numerous gastric glands. The pyloric caeca are paired. The intestine is divided into anterior, middle and posterior regions. The R.L.G. (relative length of the gut) varies from 4--5. Mucosal folds are simple.