Histology and histochemistry of the stomach and intestinal bulb of three hillstream losches.

The presence of a stomach and an intestinal bulb in three hillstream teleosts is correlated with their ecological niche and feeding habits. The intestinal bulb of G. lamta and L. guntea displays structural, enzymological and physiological features indicative of ist involvement in absorption. Evidence of an intracellular protein-digesting mechanism extending below the mucosa throughout the whole length of the intestine was also obtained in G. lamta and L. guntea. The stomach of N. savona shows gastric glands of an archaic type, without any acid-secreting parietal cells.