The efficiency would be improved by the visible intestine folds, the "plicae circulares", enlarging the absorption surface.
The jejunum has many large circular folds in its submucosa called plicae circulares which increase the surface area for nutrient absorption.
The last half of the body whorl, however, upon which the plicae become very much larger than those above, is a little convex.
The basal lip, the outer margin of the umbilicus and the parietal wall are provided with wrinkle-like plicae.
Inside the body whorl, the plicae are connected by a lunella-like ridge of callus.
Its wall is spirally striate, with a single, spiral, beaded rib and radiating plicae.
The deep umbilicus is subcircular and contains numerous slender plicae.
The body whorl is shouldered at the suture, and may be ornamented with folds or plicae.
