Figures in the Text. 



Fig. 1. 1, third ventricle; 2, lamina terminalis; 3, optic chiasm, 4, post-optic 

 sulcus; 5, corpora mammillaria; 6, area premammillaris; 7, recessus 

 mammillaris ; 8, recessus infundibuli; 9, eminentia saccularis; 10, infundi- 

 bulum; 11, processus infundibuli; 12, pars tuberalis; 13, pars infundibularis; 

 14, pars distalis; 15, lumen residuale. 



Fig. 2. 1, third ventricle; 2, lamina terminalis; 3, optic chiasm ; 5, corpora mammil- 

 laria; 6, area premammillaris; 8, recessus infundibularis; 9, eminentia 

 saccularis; 10, infundibulum ; 11, processus infundibuli; 12, pars tuberalis; 

 IB, pars infundibularis; 14, pars distalis; 15, lumen residuale. 



Fig. 3. to 10 inclusive. A sagittal series of graphic reconstructions of the 

 diencephalic floor in the plane of the median line, showing the phases 

 in the development of the neural portion of the hypophysis. 

 8 = 7mm cat embryo; 4 =10 mm cat embryo; 6^ 17mm cat embryo; 

 7 = 25mm cat embryo; 8 = 81 mm cat embryo; 9 ^51 mm cat embryo; 

 10=70mm cat embryo. 



