THE ALIMENTARY CANAL. 89 
when distended, will hold about five pints; that of the 
Kangaroo is as long as its body. 
The intestinal canal in Mammals begins at the pyloric 
end of the stomach, where there is a kind of valve or 
circular muscle. Like the stomach, it varies greatly, ac- 
cording to the nature of the food. It is generally longest 
in the Vegetable-feeders, and shortest in the Flesh-feeders. 
The greater length in the former is due to the fact that 
vegetable food requires a longer 
time for digestion, and that a 
greater bulk of such food is re- 
quired to obtain a given quantity 
of nutriment. The intestines meas- 
ure 150 feet in a full-grown Ox, 
while they are bnt three times the 
length of the body in the Lion, 
and six times in Man. Save in 
some lower forms, as the Whales, 
there are two main divisions, the 
“small” and “large” intestines, at 
the junction of which is a valve. 
The former is the longer of the 
two, and in it digestion is com- 
pleted, and from it absorption 
takes place. The large intestine is Fre. 56—Section of the Wall of 
a temporary lodging-place for the x 50: a, villi; band, amie 
useless part of the food, until it is enh aes ane 
expelled from the body. The be- ‘inal muscles. 
ginning of the small intestine is called the duodenum, 
into which the ducts from the liver and pancreas open. 
The intestinal canal has the same structure as the stom- 
ach, and by a peristaltic motion its contents are propelled 
downward. The inside surface of the small intestine is 
covered with a host of thread-like processes (vil/?), resem- 
bling the pile of velvet. 
ria BeerereAlS 
eae Ss SF 
~ hen 
