The Digestive System 187 
power drawing of the posterior region is shown in 
Figure 52. The anterior and posterior regions of 
the large intestine do not differ from each other 
sufficiently to make it worth while to represent 
both by drawings. Had an entire section through 
either region been drawn it 
would be seen that the wall 
is of very different thickness 
in different places, as was 
noted in connection with the 
small intestine; the posterior 
section was drawn where the 
wall was thin. 
It might be supposed that 
in the feeding season the fecal 
matter in the posterior re- 
gion of the rectum would = py. eA tie: eatineneh 
stretch the walls sufficiently of the anterior region of the 
to obliterate Lar gely the ge oa een ae 
prominent folds seen in Fig- tion; e¢, epithelium; ¢, 
ure 52, but such does not tunica propria. 
seem to be the case. The 
usual layers of the vertebrate intestine are present. 
The epithelium, shown under high magnifica- 
tion in Figure 53, is of the same character and thick- 
ness throughout, except that as the anal aperture is 
approached the columnar epithelium changes into 
the stratified variety. It consists of very tall and 
narrow columnar cells apparently in one layer, 
though it is difficult to be sure of this. With an 
