122 THE SNAIL. 



Its mucou§ membrane is thrown into longitudinal 

 folds. 



5. The intestine describes a somewhat S-shaped course, 



and is imbedded in the liver, from which it is not 

 very easy to separate it. From the stomach it runs 

 back round the first turn of the spiral, lying in a 

 groove on the outer side of the left lobe of the 

 liver, to the hinder end of the mantle-cavity, where 

 it passes into the rectum. It is superficial along a 

 great part of its course. 



6. The rectum has already been traced along the right side 



of the mantle-cavity to the anus. 



B. The Digestive Glands. 



1. The salivary glands are a pair of large white lobulated 



glands lying on the upper surface and the sides of 

 the crop, to the walls of which they are attached 

 by numerous strands of connective tissue. Their 

 ducts, which are long and slender, run forwards 

 and open into the buccal mass, one on each side of 

 the oesophagus. 



2. The liver is a very large bilobed gland, of a reddish- 



brown colour, which forms a large part of the 



visceral hump. 



a. The left lobe of the liver is the larger of the two, 



and is partially subdivided into three lobes. 

 It lies in the upper half of the first turn of the 

 spire, immediately behind the mantle- cavity, and 

 is grooved on its outer surface by the intestine. 

 It has three main ducts, which unite to open by 

 a single large aperture into the left side of the 

 stomach. 



b. The right lobe of the liver occupies the greater 



part of the second and upper "turns of the spire. 

 It is separated from the left lobe by the posterior 

 end of the crop, the stomach and the commence- 



