34 



project into the lumen. Two openings into the stomach, 

 both on the inner surface, mark the entrance of the ducts 

 from the digestive gland (fig. 13, Dg. d.). One of these 

 is situated anteriorly close to the proximal part of the 

 rectum, the other is just posterior to the point of entrance 

 of the oesophagus. 



The Digestive Gland is the largest structure in the 

 visceral mass, and extends from the pericardiac region to 

 the tip of the spire. It is brown or brown-green in colour, 

 and soft and oily in consistency, with no very pleasant 

 smell. This large gland, which is made up of fine 

 branching tubules, was formerly regarded as a u liver.'' 

 It is now agreed that this name is unsuitable, as the 

 digestive functions are more comprehensive and unite the 

 functions of the different digestive glands of the verte- 

 brate gut. It is, furthermore, the chief organ in the body 

 for absorption of digested food. 



Originally the digestive gland of the Gastropoda was 

 paired and symmetrical. In the adult Buccinum there is 

 an obvious division into right anterior and left posterior 

 lobes. The latter is much the larger of the two and 

 extends from the tip of the stomach to the end of the 

 spire. The boundary of the two regions lies at the 

 posterior end of the renal organ. The paired nature is 

 still further indicated by the fact that the tubules, of 

 which the gland is composed, open into one another, and 

 finally form two large ducts which enter the stomach, as 

 mentioned above. The posterior part of the digestive 

 gland is partially covered by the gonad which lies, 

 forming a kind of arch (fig. 58), on its dorsal surface. 



The Intestine (fig. 12, Red.), the original posterior 

 portion of the gut, is of shorter length than the oeso- 

 phagus. Owing to the torsion which has taken place in 

 development it runs forward dorsally to open into the 



