458 DISSECTION OF THE PIGEON. 



much larger than that of the rudimentary right 

 one. 



c. The posterior chamber is as in the male. 



VIII. EXAMINATION OF THE BRAIN. 



A. Removal oi the Brain. 



Cut through the skin of the top of the head along the middle 

 line, and turn the flaps aside. Expose and scrape clean the 

 bones of the roof of the skull. Slice off with a scalpel the skull- 

 roof, taking care not to injure the brain, which lies very close to 

 the bone. 



Cut away, bit by bit, the roof and sides of the skull, with 

 the scalpel and stout scissors, so as to expose the brain thoroughly, 

 leaving one ear uninjured. Remove the neural arches of the 

 first two vertebrce, and divide the spinal cord transversely. Turn 

 out the brain carefully, cutting across the several nerve-roots 

 one by one. Place the brain in a bottle of strong spirit, with a 

 pad of loose cotton-wool at the bottom, and leave it for two or 

 three days until it is thoroughly hardened. Examine it in 

 weak spirit. 



B. External Characters of the Brain. 

 1. The dorsal surface. 



a. The cerebral hemispheres are a pair of large pyri- 



form bodies closely applied to each other in the 

 median plane. Their surfaces are nearly smooth, 

 and their anterior ends bluntly pointed. 



b. The olfactory lobes are a pair of small conical bodies 



projecting forwards from the anterior ends of the 

 hemispheres. 



c. The pineal body is a small oval body immediately 



behind the hemispheres, and in the angle between 

 them. 



d. The optic lobes are a pair of smooth ovoid bodies 



at the sides of the brain, behind and rather below 

 the hemispheres. 



