80 INTRODUCTION 



a common sheath of peritoneum. In several of 

 the Glyphodont Water-snakes (Homalopsinse and 

 Hydrophiinae), the intestine is much convoluted ; in 

 Herpeton it is even longer than the body, although 

 when coiled occupying only one-fourth of that length. 

 The rectum is sometimes very short, sometimes 

 rather long, and its anterior portion may have a short 

 caecum ; it may be divided by transverse septa, with 

 median or lateral perforation. 



In snakes which swallow hard-shelled snails, the 

 anterior part of the intestine has its inner wall fur- 

 nished with zigzag muscular folds producing a reticu- 

 late 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 

 cesophagus is narrowed in front of the latter, at the 

 point where the tooth-like ventral processes of the 

 vertebrae project and pierce the wall of the cesophagus 

 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 extend- 

 ing nearly to the cloaca ; the right is usually a little 

 longer than the left, or extends a little farther for- 

 ward, or even may commence where the other ends. 



