THE PINEAL BODY 



45 



3332 



Fig. 12 Mesial view of forebrain reconstruction of 20 mm. Mustelus. X 75. 

 The unshaded area shows the cut surfaces of the reconstruction. According to 

 Tilney, 1915. 



2, chiasmatic process; 3, cerebellum; 4, chiasm; 7, epiphysis; 18, infundibular 

 evagination; 24, midbrain; 25, mammillary region; 32, post-chiasmatic eminence; 

 33, post-chiasmatic recess; 36, post-infundibular eminence; 41, supra-optic crest; 

 42, supra-optic recess; 44, telencephalon; 45, tuberculum postero-superius; 46, 

 tubercle of the floor of Schulte; 47, velum transversum. 



In the latter there is a slight tendency for the evagination to 

 become expanded as if to form an end-vesicle. It is, therefore, 

 possible at this time to recognize a stalk and an end-sac. 

 Neither in this stage nor in any subsequent period of develop- 

 ment is there evidence of a parapineal organ. The paraphysis 



