416 THE PINEAL ORGAN 



a recess called the subpineal cul de sac of Reichert. This may reach 

 forward as far as the posterior commissure or it may become obliterated 

 by adhesions. The lateral surfaces are also covered with pia mater which 



Fig. 280. — Drawing of a Medial Longitudinal Section through the Pineal 

 Region of a Human Subject showing the Relations of the Pineal 

 Organ to the Corpus Callosum, Fornix, Great Cerebral Vein, Dorsal 

 Diverticulum, and Choroid Plexus, Superior and Posterior Com- 

 missures, Quadrigeminal Plate, and the Membranes and Blood-vessels 

 at its Posterior Pole. (R. J. G.) 



Aq. C. : aqueductus cerebri. 



Cbl. : cerebellum. 



C.C. : corpus callosum. 



Ch. P. : choroid plexus. 



D.D. (S.P.R.) : dorsal diverticulum 



(superior pineal recess). 

 Ep. : ependyma. 

 F. : fornix P.B. : pineal body. 



P.C. : posterior commissure. 



O.T. : optic thalamus. 



R.P. : recessus pinealis. 



S.C. : superior commissure. 



Spl. : splenium. 



5. Col. : superior colliculus. 



Teg. : tegmentum. 



V .CM. : gr. vein of Galen. 



V. III. : third ventricle. 

 may be continued backward from the sides and apex of the organ as a 

 fold which contains between its layers vessels, nerves, and the ganglion 

 conari (Kolmer, Lowy, and Pastori). The nerve-fibres are described as 

 being of two kinds — " fine," which are the more numerous, and " coarse," 



