l.U HELIX — ALLMEXTAKV SYSTEM. 
left lobes of the liver. The pyloric orifice lies beneath ami to the right 
of the cardiac opening, the dncts of the liver or digestive gland 
entering at different points. 
The liver or digestive gland is the active organ of digestion and is 
a. very large nnecj^nally bilobed gland of a reildish-brown colour, 
composing a large part of the visceral hump and formed by a dense 
aggregation of blind, branched tubules, lined by glandular epithelia. 
The large anterior lobe is situate immediately behind' the mantle 
cavity ami partially sub-divided into three subsidiary lobes whose 
ducts unite before entering the stomach a little above the pylorus. 
The small posterior lobe occupies the summit of the spire, opening 
by a large duct near the top of the stomach almost ojiposite to the 
entrance of the combined duct from the anterior lobe. 
The organ is of very complicated function and structure (%ee p. 140, 
f. 208), being formed of calcareous, 
ferment, and hepatic or liver cells, with a 
(luantity of fat globules interspersed; the 
secretions of the ferment cells ai’e a 
l)Owerful aid to the assimilation of the 
ingested food, as they are not only 
capable of digesting proteids but also 
assist the salivary glands in the conver- 
sion of starch to sugar. The calcareous 
glands contain colourless granules of 
carbonate or phosphate of lime, which are 
assumed to be eventually utilized in the 
formation of the shell or its ejiiphragm ; 
the hepatic cells contain globules of a 
spherical form, which excrete small 
vesicles with yellowish contents. 
After leaving the stomach, the intes 
tinal canal keeps to the left side of the 
body, and follows an S-shaped course, 
imbedded within the tissues of the liver, 
first in an upward and forward direction, 
the second Hexure being held in position 
anteriorly by the cephalic or anterior branch of tTie aorta; the third 
flexure gradually approaches the right side of the body and occupies 
a more dorsal position, skirting in its course the posterior margin of 
Kig. 317. — Plan of the intestinal 
convolutions in Helix aspersa^ also 
showing how they are held in position 
anteriorly by the anterior aorta, and 
illustrating the relations of the heart 
and nephridium. 
a. auricle of the heart ; b. buccal 
bulb ; k. kidney or nephridium ; p.v. 
pulmonary vein ; r. rectum; sali- 
vary glands and ducts overlying 
crop ; st. stomach ; v. ventricle from 
which arises the aorta. 
