Digestive system and physiology of digestion in a style-bearing mesogastropod snail Cerithidea cingulata (Gmelin)

Abstract

An elaborate description of the digestive system of a style-bearing mesogastropod snail Cerithidea cingulata (Gmelin), along with its digestive glands is given in this paper. The histology and histochemistry of foregut, midgut, hindgut, digestive and hypobranchial glands have also been dealt in detail. The physiology of the digestive system of this snail has shown that the foregut secretes no enzyme, while the midgut is the site of high enzyme activity. The pH of the gut is neutral in the oral cavity, acidic in oesophagus, stomach, style sac, digestive gland and intestine, but again alkaline in the rectum. The studies on food and feeding habits of this snail have indicated that C. cingulata is a selective bottom feeder and feeds on detritus with a preference of soft fine sandy muddy substratum. Analysis of gut content showed the presence of sand grains, unicellular diatoms and minute scraps of algal filaments. Gut microflora include gelatinolytic, caesinolytic, amylolytic, cellulolytic and lipolytic bacteria. The microbes aid in digestion by splitting complex food materials into simple products to be acted upon by the native enzymes and of help in extra- and intracellular digestion.