HYPOPHYSIS CEKEBEI 575 



and the infundibular process; and (2) the pars tuberalis, which sur- 

 rounds the eminentia saccularis. 



The following outline presents this analysis in resume: 



HYPOPHYSIS CEREBRI 



I. Pars Neuralis: (Posterior lobe). 



(1) Eminentia Saccularis. 



(2) Infundibulum. 



(3) Processus infundibuli. 

 II. Pars Buccalis seu Glandularis: 



(1) Pars juxtaneuralis. (Intermediate portion.) 



(a) Pars tuberalis. 



(b) Pars infundibularis. 



(2) Pars distalis. (Anterior lobe.) 



"The pars infundibularis makes its appearance almost immediately 

 after the anlage of the buccal portion of the hypophysis is formed. The 

 pars tuberalis arises as a relatively late structure. It has its origin in two 

 secondary diverticula or sprouts from the body of the pituitary sac (buccal 

 evagination). These sprouts, the lateral processes, ultimately fuse with 

 each other across the median line, displace the body of the pituitary sac 

 ventrad" and thus secondarily assume their juxtaneural position. The 

 juxtaneural portion of the hypophysis is intimately connected with the 

 neural portion by means of nerve fibers, blood-vessels and connective 

 tissue processes. Attempted separation consequently necessarily includes 

 laceration of neural elements" (Tilney). Accordingly complete removal of 

 the pars buccalis would seem to be impossible without the attendant re- 

 moval of portions of the pars neuralis. This must be taken into account in 

 interpreting symptoms following removal of the anterior lobe of the hypo- 

 physis. 



I. PARS NEURALIS : INFUNDIBULUM. This consists of fusiform and 

 multipolar neuroglia cells and fibers. A substance resembling colloid is 

 also occasionally present. Small nerve cells have been reported, but 

 their presence seems doubtful. The glia cells generally have a single 

 nucleus, but two or more may appear. The protoplasm is finely granu- 

 lar, and occasionally contains pigment granules, which seem to be more 

 abundant in aged specimens. Delicate and coarse glia fibers extend 

 through the protoplasmic portions of the cells, frequently terminating 

 the cell processes (Fig. 496). 



II. PARS BUCCALIS SEU GLANDULARIS: (1) Pars juxtaneuralis. 



