THE PINEAL BODY 9 



by means of a short, slightly constricted piece, the peduncle. 

 The parapineal organ, likewise, has an end-sac, a stalk, and a less 

 well defined proximal portion. Much variation exists in the 

 forms presenting these several parts in many instances, one or 

 more of the parts described may be absent, yet, to make the 

 terminology as comprehensive as possible, all of these portions 

 should be included. Upon this basis the following constituents 

 may be recognized in the epiphyseal complex: 



I. The pineal organ, consisting of: 



1. An end- vesicle. 3. A proximal portion. 



2. A stalk. 4. A peduncle. 



II. The parapineal organ, consisting of: 



1. An end-vesicle. 3. A proximal portion. 



2. A stalk. 



The proximal portion and peduncle of the pineal organ cor- 

 respond to the epiphysis or corpus pineale of mammalian anat- 

 omy. The proximal portion is probably analogous to the cellu- 

 lar part of the pineal body while the peduncle is comprised 

 largely of nerve fibers. 



3. GENERAL REVIEW OF THE LITERATURE 



Galen (1576) 138 gave a description of the conarium in its rela- 

 tion to the third ventricle as well as to the chorioid plexus and 

 blood vessels about it. According to his interpretation, the 

 organ serves as the support for the great vessels converging upon 

 that portion of the brain. Oribasius (1554) 285 mentioned but 

 did not describe the epiphysis. Uvarthonus 401 believed that 

 delicate nerve fibers enter the pineal body; these fibers seem to 

 take origin in the lower portion of the spinal cord. Bauhinus 

 (1616) 16 considered the conarium to be a glandular structure 

 related to the chorioid plexus. Diemerbroeck (1633) 91 showed 

 certain differences between the pineal body in man and in other 

 mammals. Dionis (1706) 93 described the pineal body as attached 

 upon either side to the chorioid plexus by a small hand. This 

 band may be a nerve derived from the sympathetic system. 



