3M 



THE PINEAL ORGAN 



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Fig. 217. 



A — Transverse section through the distal end of the pineal evagination of a 

 6-cm. human embryo. It shows folding of the wall of the diverticulum and 

 outgrowth of the proliferating ependymal cells into the mantle zone. 



B — Section through the pineal region of an adult Sphenodon (Dendy collection), 

 showing in the upper part of the photograph the pineal evagination, the wall 

 of which is folded in a manner similar to the human, but the extension of 



[Continued at foot of next page 



