204 



Plate V. 



Fig. 34. A dissection from above to display the various 

 parts of the alimentary canal. The dorsal 

 part of the body has been removed, as well as 

 the gonads. The gills are not shown. The 

 digestive gland is only shown on the left side. 



Fig. 35. Vertical transverse section through the 

 oesophagus, to show especially the oesophageal 

 glands. x 35. 



Fig. 36. Transverse section through the pyloric region 

 of the fore-gut. x 30. 



Fig. 37. Transverse section through a tubule of the 

 digestive gland. x 120. 



Fig. 38. A "fat cell" of the digestive gland. x 430. 



Fig. 39. A " ferment cell " of digestive gland, x 430. 



Plate VI. 



Fig. 40. The fore-gut from the left side, showing the 

 ossicles. x ]A. 



Fig. 41. The pyloric region of fore-gut, dorsal view, x 3. 



Fig. 4L/. Anterior view of the pro-pyloric ossicle, x 4. 



Fig. 42. Transverse section through the region of the 

 green gland, to show the parts of the bladder. 

 Only one side shown. x 8. 



Fig. 43. The ossicles of gastric mill, from above, x 2. 



Fig. 44. The ossicles of the gastric mill, from below. 

 The fore-gut has been opened ventrally. The 

 left zygocardiac ossicle has been rotated in 

 order to show the lateral teeth. x 3. 



Plate VII. 



Fig. 45. The fore-gut from the left side, showing the 

 intrinsic and extrinsic muscles. x 3. 



Fig. 40. Anterior view of the fore-gut, to show the 

 muscles. x 11. 



Fig. 47. The fore-gut from above, showing the intrinsic 

 and extrinsic muscles. x li. 



