140 JOURNAL OF ENTOMOLOGY AND ZOOLOGY 



radula, as the cavity narrows. About half way between the 

 two ends of the linccal mass the oeso]iliagus branches off on the 

 upper side, but the buccal food cavity does not end when this 

 takes place, but extends as a blind pocket nearly to the end of 

 the buccal mass. 



Close to the point where the oesophas'us branches otT, minute 

 ducts from the salivary glands enter the buccal food cavity, one 

 on each side. These glands are long, unbranched tubes, lined 

 with cubical epithelial cells. They lie loosely in the body cavity 

 back of the buccal mass, and in two specimens examined the 

 ends were fused. 



After leaving the buccal mass the oesophagus goes back be- 

 tween the ganglia of the central nervous system, gradually be- 

 coming larger, passes below the liver, and enters the stomach on 

 the under side. The stomach itself is rather small but communi- 

 cates with the liver by numerous large openings, so as to make 

 its actual capacity considerably larger. The stomach is lined, 

 as are the oesophagus and intestine, with ciliated epithelium. 

 The liver consists of branching tubes lined with tall columnar 

 cells with a fine granular protoplasm. On the iipper side of 

 the stomach is a cpecum, about twice as large as the intestine, 

 in diameter, which is lined with glandular cells of a different 

 character than those of the liver. Directly in back of this 

 caecum the intestine leaves the stomach. It runs forward over 

 the surface of the liver to the extreme anterior end, then curves 

 to the right and runs back to a point just beneath the branchiae, 

 where it becomes slightly enlarged and laminated and curves 

 upward to open within the circle of the branchial plumes. 



The Nephridium. The kidney is a thin-walled sac with many 

 ramifications that cover the whole surface of the liver mass and 

 extend for a short distance down the sides. The walls are 

 formed by a single layer of large, cubical granular cells on a 

 very thin liasement membrane. These contain round, dark- 

 staining nuclei and a small amount of protoplasm near the base, 

 the rest of the cell usually being clear. The kidney communi- 

 cates with the pericardium near the point where the right 

 lateral siniis enters the right auricle, by means of a tubular 



