THE FRESH-WATER MUSSEL. 



109 



ach. I wonder if the poor anodon (another name for 

 the mussel, meaning toothless) ever gets bilious, and if 

 his doctor makes him take " liver-pills? " He may not 



Fig. 102. 



Under Part of Kidney. Large Vein— Vena Cava. 



suffer from bile, but I should not be surprised if he had 

 nervous attacks like neuralgia, he has so many nerves. 

 At each side of his mouth, and at the base of the palps, 

 is a little mass of yellow nerve-matter about the size of 

 a pin-head (Fig. 103). Each mass is called a ganglion, 

 which means a bunch, or swelling. The two bunches 

 — -ganglia — are united by a w r hite nerve-cord, which 

 forms h loop above the gullet, or oesophagus (Fig. 103). 

 These " bumps " are our friend's brains, though he has 

 no head to put them in. No doubt you all think it bet- 

 ter to have brains without a head, than a head without 

 brains. Another cord leads from each head-bump, or 

 ganglion, down to the foot, where it joins another little 

 mass of nerve-matter, one on each side of the front of 

 the foot (Fig. 103). These are the pedal or foot gan- 



