466 THE PINEAL ORGAN 



epithelium is columnar in type, to larger cysts which are formed, as is 

 indicated by septa projecting into the lumen, by the coalescence of adjacent 

 smaller cysts. The lining membrane in the larger cysts, found in old 



Fig. 318. — Case 9. Drawing of a Longitudinal Section of the Pineal Cyst, 

 and the Suprapineal Recess above it, D.D. (R. J. G.) 



A. : anterior end. P. cyst. : lumen of the pineal cyst. 



C.V. : choroidal villi projecting into P. : posterior end. 

 the lumen of the diverticulum. 



subjects, is formed by flattened cells which have been described as 

 " pseudo-ependymal." Whether these cells are responsible for the 

 secretion of the fluid which fills the cyst or whether this fluid is derived 

 from the vessels supplying the gland appears to be undetermined. 1 



1 Further information on the development and nature of pineal cysts will be found in 

 an article by Eugenia R. A. Cooper in the J. Anat., 67, 1932-3, p. 28. 



