56 
ZOOLOGICAL EXERCISES. 
at the bottom of the body cavity, just 
where the foot becomes entirely muscular, 
and about one-third of its length from the 
anterior end. They are of a yellow colour. 
Take the parieto-splanchnic ganglion first, as it is: 
the easiest found, and trace forwards the nerve joining 
it to the cerebral ganglion. It passes across the 
organ of Bojanus and along the dorsal aspect of the 
animal. If you lose it, search for the cerebral gan- 
glon, and try to trace the nerve from it to the pedal 
ganglia. If you lose this, search for the pedal gan- 
glia by gently scraping away the muscular tissue 
of the foot over the place. 
9. Alimentary and reproductive systems.—Cut open the 
body cavity along the dorsal margin. Lift up the 
edge with the forceps, and carefully detach it from 
the contained viscera, cutting the muscular coat 
anteriorly and posteriorly, and lay it back over the 
foot. Observe the labial palps, lying just inside the 
anterior adductor; there are two on each side. Cut 
one off and examine. It is longitudinally striped 
and richly ciliated. 
The liver, lying near the dorsal part of the 
cavity. It is of a deep green colour. 
The reproductive organs, filling the rest of the 
cavity; pale orange or white. Examine. 
In the ova notice the projecting portion of 
albumen, through which, with slight pres- 
sure, the yolk escapes. This is the mzcro- 
pyle. 
Remove the liver and as much of the reproductive 
organs as possible, by means of a knife, forceps, 
and brush. Notice the alimentary canal. A short 
cesophagus leading into a capacious stomach, which 
