In snakes which swallow hard-shelled snails, the anterior part of the intestine has its inner wall furnished with zigzag muscular folds producing a reticulate appearance, followed farther down by transverse and then longitudinal folds. In these snakes the intestine is abruptly constricted behind the stomach, at which point the shells are broken or crushed after their contents have been digested; whilst in the egg-eating snakes, in which the eggshell has to be broken previous to its contents reaching the stomach, the oesophagus is narrowed in front of the latter, at the point where the tooth-like ventral processes of the vertebræ project and pierce the wall of the oesophagus in order to aid in this function, after which the broken shell is rejected through the mouth. The more or less elongate, feebly-lobed kidneys are placed in the posterior part of the body, often extending nearly to the cloaca; the right is usually a little longer than the left, or extends a little farther forward, or even may commence where the other ends. The suprarenal bodies are narrow and elongate, placed on the renal veins or on the vena cava inferior. The ureters leave the hind ends of the kidneys, and open through the side-walls of the cloaca on a papilla which in the males contains also the opening of the vas deferens. There is no urinary bladder. The genital organs will be mentioned in the next chapter. The liver is usually long and narrow, measuring one-fifth to one-fourth the length of the body, on the right side of the alimentary canal, commencing just behind the heart or farther back. It is exceptionally short in _Chersydrus_. It is sometimes divided by transverse furrows. Its posterior extremity is bilobate, and the left lobe usually extends beyond the right, although the reverse has been observed in some snakes. The gall-bladder, which may be absent, is remarkable for its distance from the liver. The pancreas, elongate but comparatively small, is located near the spleen, on the left side of the alimentary canal, at a considerable distance from the liver. The peritoneal part of the body-cavity is subdivided into a number of spaces or coelomic compartments enclosed in serous capsules--viz., a posterior or intestino-genital, a gastric on the left side, and a pair round the liver, corresponding to its two lobes. Fat-bodies are much developed, either in the form of small separate lobes, or as a continuous, much folded band, on each side of the body. ------------------------------------------------------------------------ CHAPTER IX ORGANS OF REPRODUCTION; PAIRING; OVIPOSITION; DEVELOPMENT