222 ANIMAL ACTIVITIES. 
Do you find the visceral cavity divided by a thin 
muscular wall (the diaphragm)? Isthere a diaphragm 
Skeleton of Bat Showing Wings. 
Fic. 180. 
in the frog or fish? Inthe bird? How does the dia- 
phragm assist in breathing ? 
Can you find the lungs and heart? Are they an- 
terior or posterior to the diaphragm ? 
