68 
middle lines of the latter, and suspends the stomach and 
the greater portion of the intestine, but not the duodenum. 
It is curious that the anterior two-thirds of the stomach 
are attached to this mesenteric sheet along the mid-dorsal 
line, but towards the latter third the attachment is on the 
right side, as if the stomach had been longitudinally 
rotated from left to right. This mesentery is of course a 
double sheet of membrane which encloses the urocyst and 
ureter. A second, apparently distinct mesentery takes 
origin over the internal surface of the liver, and is 
attached to the duodenum and to the greater portion of 
the succeeding intestine. The latter is therefore attached 
to other parts by means of two mesenteric sheets. The 
second mesentery described above covers over the spleen 
and bile duct. 
The Liver (figs. 20 and 21) is asymmetrical. It con- 
sists of two lobes connected by an anterior isthmus of 
hepatic tissue. The larger of these lobes forms a flat cake 
lying on the eyeless side of the body cavity, and the 
smaller lies in the anterior and dorsal corner of the ocular 
side, its anterior surface being in contact with the pos- 
terior wall of the pericardium (Per. fig. 20). The organ 
is suspended to the body cavity wall by the two hepatic 
veins (V. hep. fig. 21) which penetrate the posterior wall 
of the pericardium, and by a fibrous sheet passing be- 
tween these and attaching the pericardial septum to the 
anterior surface of the liver. This anterior surface, as 
well as the lateral, is smooth, but the internal surface on 
the other hand is thrown into lobules (fig. 21) by deep 
furrows in which the factors of the hepatic portal system 
run, and along which they can be traced for considerable 
distances.. | 
The Gall Bladder (figs. 20 and 21) lies wedged in 
between the right hepatic lobe, the right surface of the 
