8 The Shell-Collector’s Handbook. 
the intestine, which makes a S-shaped turn through 
the digestive gland, and then passes into the rectum, 
which runs along the right side of the mantle cavity 
to the anus. This digestive gland has two lobes—a 
right and a left. The right lobe lies in the upper” 
half of the body whorl, and is divided into three 
lobes, each lobe possessing a duct of its own. These 
ducts, however, unite into a common duct before 
emptying themselves into the right side of the 
stomach. Theleft lobe is situated in the upper turns 
of the spiral. It has one duct which opens on the 
left side of the stomach, nearly opposite the common 
duct of the right lobe. Three kinds of cells have 
been demonstrated as existing in this so-called liver, 
or digestive gland. One set becomes black on treat- 
ment with osmic acid (ferment cells); another con- 
tains calcic phosphate and calcic carbonate, and is 
concerned in the function of producing the epiphragm 
(calcareous or calciferous cells); while the other set 
(hepatic cells) excrete yellowish-looking globules, which 
are passed away with the feeces, and which, in my 
thinking, serve the same function in the snail’s 
economy, as the bile in the human body. 
THE CrrcuLaTiIne System.—The pericardium is 
oval, about an inch in length in the largest species, 
and placed to the left of the kidney, and in the roof 
of the mantle cavity. It is in communication with 
the kidney by a canal—the reno-pericardial canal. 
The heart consists of a thin-walled azricle and a 
thick-walled ventricle, separated from each other by an 
auriculo-ventricular valve. From the front end of the 
ventricle the aorta arises, and immediately divides 
