126 ANATOMY OF THE R.ABBIT 



The conical pineal body, or gland (epiphysis cerebri), which 

 is the rudimentary third eye of certain lower animals, is attached 

 by a hollow stalk to the thalamencephalon. It Hes in the 

 triangle formed by the cranial margin of the cerebellum and 

 the two dorsal caudomedial angles of the cerebral hemispheres. 

 The cleft in which the stalk of the pineal gland lies is the dorsal 

 portion of the third ventricle of the brain. 



The pituitary gland (hypophysis cerebri) is about 7 mm. 

 long and 4 mm. wide and Hes caudad to the optic chiasma, in 

 the pituitary fossa of the sella turcica which is surrounded by 

 the sphenoid bone. Since this gland is more firmly attached 

 to the pituitary fossa than to the brain, it is usually accidentally 

 detached from the latter. In this case the sht-like aperature 

 of the third ventricle, with which the pituitary gland was 

 connected, will appear as in figure ^,7,. 



Method: The entire brain and about two inches of the spinal 

 cord with the roots of the cranial nerves and at least one pair of 

 vertebral nerves and as much of the membraneous covering 

 (meninges) as possible should be removed together. The 

 object in remo\dng the meninges with the brain is to protect 

 the delicate nervous tissue and to include the arteries. The 

 floor of the first two or three cervical vertebrae should be left 

 attached to the spinal cord for its protection and to show rela- 

 tions of vertebrae, spinal nerves and cord, and vertebral arteries. 



The flesh is removed from the dorsal region of the skull and 

 the roof of the cranium cracked, but not crushed, by a few 

 sharp blows with the handle of the cartilage knife. Then, 

 the fragments of the bone are carefully picked off with the 

 cartilage knife and large forceps, and then the pedicles of both 

 sides of the cervical vertebrae are carefully cut through with 

 the bone cutters. After this is completed the brain is loosened 

 from the other half of the skull and very carefully removed. 



After the brain has been removed and carefully examined, the 

 meninges may be slit with scissors along one side of the median 

 fissure of the cerebrum and into the olfactory tissue which 

 will probably have been removed with the brain. 



