194 
ANIMAL ACTIVITIES. 
commonly large and when deposited for hatching out¬ 
side of the body are covered with a limy shell. A 
Fig. 153.—Brain of 
Frog. 01 , olfactory 
lobes; CH, cerebral 
hemispheres ; OpL, 
optic lobes ; Cl, 
cerebellum; MO, 
medulla oblongata. 
peculiarity of the skull of Reptiles is the presence of 
the quadrate bone, a characteristic shared also by 
birds. 
