140 THE FROG CHAP, vin 



with goblet-cells amongst them ; and a deeper connective-tissue layer, 

 the submucosa^ enclosing vessels and nerves. 



I). Muscular layer : an external longitudinal, and an internal circular 

 layer of unstriped muscular fibres. 



c\ Peritoneal layer. This is very thin, and a careful examination 

 of good preparations is required in order to make out its structure 



(P- 131). 

 Sketch. 



3- Transverse section of stomach (Fig. 40). After recognising 



the layers as above, note : 



a. The gastric glands ^ and b. the muscnlaris untcosce. 

 Sketch. 



4- Sections of liver (Fig. 41). 



a. Polyhedral gland-fells^ arranged in columns ; b. bile-passages and 

 ducts ; c. blood -capillaries and vessels. 

 Sketch. 



5- Sections of pancreas (Fig. 42). 



a. Lobules, separated by connective-tissue, and each consisting of 

 gland-cells ; b. ducts. 

 Sketch. 



