244 FREDERICK TILNEY 
cephalad and is relatively thick and the other which faces caudad 
and is thin. Both of these surfaces are closely invested by the 
pars infundibularis of the pituitary gland and their continuation 
laterad produces two long and slender lateral processes. The 
39 
ye ay 
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ipo 
iH 
13 
Fig. 13 Mesial view of forebrain reconstruction of 51mm. catembryo. X 50. 
The unshaded area shows the cut surfaces of the reconstruction. 2, chiasmatic 
process; 4, chiasm; 5, corpus interpedunculare; 7, epiphysis; 9, foramen of 
Monro; 11, infundibular stem; 13, infundibular process; 20, lamina terminalis; 
27, mammillary body; 32, post-chiasmatic eminence; 33, post-chiasmatic recess; 
35, post-infundibular recess; 36, post-infundibular evagination; 39, paraphysis; 
40, recess of the infundibular process; 42, supra-optic recess. 
brain floor in the mammillary region is still further increased 
in thickness and two definite lateral protuberances, one on either 
side of the median line, have made their appearance. Because 
of the increased thickness of the neural tissue which bounds 
them the lateral diverticula of the mammillary recess have 
