144 LILIAN SHELDON. 



their protoplasm is rich in granules, and at their free ends 

 many of them are prolonged into blunt processes (fig. 6), which 

 project into the lumen, and only stain very faintly. In most 

 of the cells these processes are not visible, but since they other- 

 wise resemble those that have them, the difference would seem 

 to be due to their being in a different stage of secretory 

 activity. In such cells the end abutting on the lumen stains 

 more deeply than the rest of the cell, and the two regions are 

 separated in preserved specimens by a row of very deeply- 

 staiuing dots. Among the cells a few leucocytes are scattered 

 (fig. 6, /.). The glands are separated from one another by a 

 portion of the pseudocoele. 



The intestine is lined throughout by rather short, ciliated 

 columnar cells (figs. 11, Ep. Int.). 



When the intestine is viewed as a whole it is seen to be 

 enlarged for a short distance (fig. 4, Int. L.) soon after leaving 

 the stomach. This appearance is due to its being surrounded 

 by the so-called liver-cells. These are large and oval, are 

 closely applied to the wall of the intestine, and form a compact 

 mass round it. In the fresh state they are bright orange in 

 colour. Each cell is pear-shaped with its thin end in contact 

 with the epithelium of the intestine (fig. 11, L.), and is sur- 

 rounded by a somewhat thick fibrous coat (/. /.), which is 

 thickest at the broad end of the cell. In preserved specimens 

 the cells are filled with a coarsely granular substance (fig. 11, 

 g. I.), which is mostly aggregated at the narrow ends, and con- 

 tains highly refractive concretions. 



I could not find any connection of these cells, either with 

 one another or with the intestine, but it seems possible that as 

 they lie so closely applied to the wall of the intestine, their 

 contents may pass into its lumen between the epithelial cells, 

 the passages being so small as to have escaped my notice. I 

 am unable to offer any suggestion as to their probable function. 



The Heart. 

 The heart is a long, thin-walled vessel, lying in a pericardium, 

 which is considerably larger than itself. 



