A comparative study of feeding and digestion in the freshwater Cuttus gobio and the marine Enoghrys bubnlis has been made. The digestion of live prey taken voluntarily, and of aqueous starch suspensions and of olive oil administered by stomach tube, are described at the macroscopic and histological level. Particular attention has been paid to the food capacity of the gut, the mechanical treatment of the food, and the role of mucus in the alimentary tract.Digestion, which is similar in the two species, is divided into three distinct phases, corresponding to the three morphologically separate regions of the post-pharyngeal gut. The relative roles of each of the three regions in the digestion and absorption of food are assessed.No modification of gut structure or function in either species directly attributable to environmental salinity has been detected. The evidence suggests that the faster growth rate of the marine species may be due to the greater digestive-absorptive capacity of its digestive system.

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The diet and feeding mechanism in Cottus gobio and Parenophrys bubalis are described, together with the morphology and histology of the alimentary tract. Both species are sluggish bottom dwelling, carnivorous fish, and are capable of catching and swallowing relatively large prey. The gut is fully differentiated into esophagus, stomach, intestine with pyloric ceca, and rectum. The liver is morphologically separate from the pancreas, and separate bile and pancreatic ducts open into the base of one of the pyloric ceca. The organisation of the gut is well suited to the fishes' mode of life, showing adaptations for taking large meals which may be at irregular intervals.

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