SMALLWOOD. — POLYCERELLA ZOOBOTRYON. 



617 



lar part of the liver they surrouud, is filled with the same granular 

 cytoplasmic mass containing vacuoles, the cell apparently breaking 

 down after it becomes filled with the 

 hepatic secretion. The gland cells 

 are long and irregularly flask-shaped, 

 the neck being attached to the base- 

 ment membrane (Figure 6,/). The 

 liver cells apparently regenerate the 

 portion which breaks down, as there 

 are no small basal cells and the large 

 nucleus near the base of the cell is 

 surrounded by numerous compactly 

 arranged cytoplasmic granules. In 

 the minute ducts leading into the 

 bile sac the cells are more regular 

 and much shorter (Figure 6, e), while 

 those lining the bile duct itself are 

 ciliated. 



5. The Kidney. 



The nephridial organ (Figure 3, 

 ren.) covers the upper surface of that 

 portion of the posterior visceral mass 

 which lies to the right of, the esoph- 

 agus and j ast anterior to the stomach. 

 It does not extend down over the 

 right side and usually does not exceed 

 40 micra in width. It consists of an 

 irregular number of tubules immedi- 

 ately ventral to the pericardium. The 

 cells are polygonal, their free ends 

 being mostly transparent and appar- 

 ently without concretions. A short 

 duct connects the kidney with the 

 real chamber (cam. ren.), which is 



FiGUHE 6. a, Ciliated cells from 

 the mouth of the prostate duct; b, 

 ordinary lining epithelial cells from 

 prostate duct; c, cells from edge of 

 glandular patch of prostate gland; 

 d, cells of glandular patch of pros- 

 tate gland; sec, secretion; c, cells 

 from duct leading from hver lo- 

 bules; f, hver cells. All drawn with 

 camera lucida, one inch ocular, 

 and one-twelfth inch oil immersion 

 objective. X 612. 

 a large bilobed sac. The dorsal lobe 

 is 80 micra long, being much longer than the ventral lobe (50 micra). 

 This large sac, 90 micra wide and 70 micra deep in its greatest extent, 

 lies over the esophagus and projects beyond the anterior margin of the 

 posterior genital mass (Figure 3, com. ren.). On the floor of the renal 

 chamber there is a fold which nearly fills the passage into the kidney 

 and is covered with long cilia. There seems to be a minute pore 



