An Analysis of the Juxta-Neural Epithelial Portion etc. 265 



saccular eminence of the tuber cinereiim, the infundibulum and in- 

 fundibular process. Furthermore, the portion of the glandular tissue 

 in contact with the pars neuralis constitutes the juxta-neural epi- 

 thelial portion of the giand. This portion in turn comprises two 

 distinct elements, the pars tuberalis surrounding- the eminentia saccu- 

 laris, and the pars infundibularis surrounding the infundibulum and 

 infundibular process. 



The three portions of the gland differ not only because of their 

 relative positions but quite as much because of their distinctive 

 histological characteristics. 



1. Histological characters of the pars tuberalis (plate XVI, fig. 26). 



a) Cellular arrangement. The cells in this portion of the gland 

 give the characteristic appearance of being arranged as many large 

 acini, each acinus containing colloid material. The cells in the walls 

 of the acini are high cuboidal and often two layers deep. 



b) Cells. The cells themselves are basophilic, their cytoplasm 

 scanty and homogeneous, while their nuclei are large and vesicular; 

 they stain deeply. 



c) Vascularity. The blood vessels and blood spaces in this region 

 are numerous. 



2. Histological characters of^ the pars infundibularis (plate XVI, 

 fig. 28). ' 



a) Cellular arrangement. The cells here are arranged in a dense 

 stratum several layers deep. Occasional acini appear in this region 

 but these differ from those of the tuberai portion in that they are 

 smaller and lined by low cuboidal cells which never exceed a single 

 layer in thickness. 



b) Cells. The cells have an ample cytoplasm, are faintly baso- 

 philic and granular. The nuclei are large, vesicular and centric. 



c) Vascularity. The vascularity of this part is almost neglibile. 



3. Histological characters of the pars distalis (plate XVI, fig. 27). 



a) Cellular arrangement. The cells are arranged in dense convo- 

 luted cords. — A narrow zone of basophilic cells invests the pars 

 distalis. 



b; Cells. The cells are large, granular and deeply acidophilic. 



