THE PINEAL BODY 



71 



with the exception of a very small lumen which extends almost 

 throughout its entire extent. A very large pineal recess is 

 present. The dorsal sac and paraphysis are both much reduced 

 in size. There is no evidence of any distal portion of the pineal 

 organ at this period. No sign of an evagination or anlage which 

 might be interpreted as the parapineal organ was found in this 

 study. 



39 



Fig. 38 Mesial view of forebrain reconstruction of 14 days and 18 hours chick. 

 X 25, according to Tilney, 1915. 



1, aqueduct of Sylvius; 2, chiasmatic process; 3, cerebellum; 4, optic chiasm; 7, 

 epiphysis; 9, foramen of Monro; 12, infundibular canal; 14, infundibular process, 

 saccular surface; 15, infundibular process, pituitary surface; 24, midbrain; 26, 

 mammillary recess; 27, mammillary body; 32, post-chiasmatic eminence; 33, post- 

 chiasmatic recess; 36, post-infundibular eminence; 38, pre-chiasmatic recess; 39, 

 paraphysis; 41, supra-optic crest; 42, supra-optic recess; 44, telencephalon. 



