180 INVERTEBRATE ZOOLOGY 
Make a cross section through the gullet and study the arrange- 
ment of the mesenteries, the relation of the primary mesenteries 
to the gullet, and the longitudinal muscles. 
Exercise 3. Draw a diagram of the cross section, showing these 
features. 
Make a cross section through the body beneath the gullet. 
Exercise 4. Draw a diagram of the cross section, showing the 
arrangement of the mesenteries. 
