THE PIGEON. 115 



THE BRAIN OF THE PIGEON. 



Cut away the top of the skull with a sharp knife, using 

 great care not to injure the soft brain, and make out the 

 following parts : — 



1. In front, the large cerebrum, consisting of two hemi- 

 spheres, which are separated by a deep groove. 



2. Behind the cerebrum is the undivided cerebellum. 



3. Running backward from the under side of the cere- 

 bellum is the spinal cord; trace it back into the 

 backbone. Make drawings of the brain, as seen from 

 above and as seen from the side. 



THE SKELETON OF THE PIGEON. 



Notice the lightness of the whole skeleton. What part 

 of the pigeon's weight is bone? Compare the eye-cavity 

 with that of man. The lower jaw does not join the skull 

 directly, as in man, but is joined to an irregular bone, 

 which, in turn, joins the skull. This is the quadrate bone= 

 The hole by which the spinal cord leaves the brain-cavity 

 is the occipital foramen; in front of this foramen is a 

 little rounded projection, the occipital condyle. Observe 

 how this condyle fits into a cavity in the first vertebra of 

 the neck. Count the vertebrae of the neck, or cervical 

 vertebrae. Observe the consolidation of the vertebrae in 

 the back; note the joint in each rib, and the arrangement 

 for bracing the ribs together. Press the breastbone alter- 

 nately toward the back and away from it, meanwhile 

 watching the joints in the ribs. 



