98 INVERTEBRATE ZOOLOGY 
cerebro-visceral connective, which goes to the visceral ganglia, the 
cerebro-pedal connective, which goes to the pedal ganglia, and 
the pallial nerve, which passes to the mantle. Find them. 
The pedal ganglia form a nervous mass buried in the foot 
near its base. Make a shallow longitudinal incision in the bot- 
tom of the foot and gently pull the flaps apart; the pinkish 
mass and the nerves radiating from it will be seen. In contact 
with it is a sense-organ called the otocyst. 
Exercise 10. Draw a diagram representing the nervous system. 
Make several transverse sections with a razor through the 
region of the heart of a mussel which has been previously 
hardened. Identify all the organs which appear. 
Exercise 11. Draw a diagram representing a cross section; care- 
fully label all the organs. 
