A LAND SNAIL 119 
the inner surface of the whorl. The light-colored hermaphroditic 
gland will be exposed. Remove, then, the delicate integument 
which covers the outer surface of the whorl, and the dark-brown 
liver will be exposed. Press the liver away from the intestine 
and completely free it, without, however, breaking either liver 
or intestine. Great care should also be taken not to injure the 
hermaphroditic gland, which is the yellowish mass on the inner 
side of the last whorl, or the hermaphroditic duct leading away 
from it. Note that the liver is composed of two masses, the 
smaller of which is of spiral form and occupies the apex of the 
shell; the larger is subdivided into three lobes. Note also 
the two main bile ducts which join the liver with the intestine. 
The visceral artery will be seen lying upon the liver, sending 
branches off on both sides, and must not be confused with 
the bile ducts, which it resembles in appearance. It carries 
blood from the aorta to the top of the spiral, supplying all the 
organs of the visceral mass. At the point where the bile 
ducts communicate with the intestine that organ makes a 
sharp turn. 
Spread out the digestive tract to the animal’s left and pin it 
down, without, however, removing or breaking the hermaph- 
roditic gland or duct. The stomach will be seen to extend 
nearly to the liver. It is succeeded by the intestine, which 
soon makes the sharp turn above mentioned, receives the bile 
ducts, and passes into the rectum at the right side of the 
mantle cavity. 
Exercise 5. Draw an outline of the alimentary tract from the 
mouth to the anus on a scale of 2 and label all its 
parts. 
Study the structure of the pharynx. Pass a probe into the 
mouth and notice the extent of the pharyngeal cavity. Notice 
the transverse horny jaw in the roof of the mouth. With a 
sharp knife split the dorsal pharyngeal wall, taking care not to 
