The nudibranch family Dironidae. 597 
tact with the intestine, its posterior and left borders and dorsal 
surface with the stomach. Its duct joins the duct of the dorsal 
lobe as the latter enters the stomach. 
The cells of the liver are cubical and vacuolated, with compact, dark 
nuclei. Granular inclusions of several kinds are numerous, but no detai- 
led cytological study has been made of their nature. In life the liver has 
a dark green color, but to what this may be due has not been determined. 
The intestinal wall is thin with a slightly developed muscular 
layer. Its inner surface presents numerous longitudinal ridges, and 
is covered with a layer of columnar ciliated cells, which continue 
uninterruptedly to the canal opening. In the finely divided contents 
of the alimentary canal but little can be distinguished save diatom 
shells and minute spicules. T’hese make up a very small proportion 
of the total contents. 
Exceretory system. The kidney is a thin-walled sac lying imme- 
diately beneath the pericardium on the dorsal surface of the visceral 
complex, and sending complicated ramifications over its surface, and 
down in the interstices between the lobes of the hermaphroditic 
eland, the liver and the alimentary tract. These branches are 
irregular in form and terminate in slightly dilated tips. They are 
lodged in the loose connective tissue, so that with some care the 
whole organ may be dissected out from its attachments and isolated. 
Two main superficial branches may be distinguished, extending from 
the central elongated chamber. One of these passes transversely 
toward the left side, enveloping the anterior region of the visceral 
complex and extending laterally down to the foot. The second 
branch passes backward and ramifies over the posterior median and 
lateral surfaces. Two other branches of unequal size, and several 
minor ones arise from the central surface of the ventral chamber 
and pass downward between the organs of the visceral complex, 
The largest of these is directed downward and backward, following 
the hermaphroditie duct, while the smaller passes downward toward 
the left, and forward between the stomach, the liver lobes and the 
proximal intestine loops. The reno-pericardial opening is found ın 
the renal syrinx, a conspicuous pyriform body situated midway of 
the animal’s length, upon the right dorsal surface of the visceral 
complex. It communicates below with the cavity of the kidney, and 
above with the pericardial cavity, opening through the floor of tlıe 
right side. Its lumen is divided by numerous folds of the wall, 
many of which in turn bear secondary folds.. The complicated 
