Complex sentence: They are composed of reduplications of the mucous membrane, the two layers of the fold being bound together by submucous tissue; unlike the folds in the stomach, they are permanent, and are not obliterated when the intestine is distended.
Split into simpler sentences: They are composed of reduplications of the mucous membrane, the two layers of the fold being bound together by submucous tissue. Unlike the folds in the stomach, they are permanent, and are not obliterated when the intestine is distended.