NO. 16 DUCTLESS GLANDS OF THE ALLIGATOR REESE II 



with the middle region. It is surrounded by the fairly thick capsule 

 (c) already mentioned, in which blood vessels (bv) are to be seen. 

 An occasional colloidal cyst may be seen, as at cy. 



The finer structure of the hypophysis will now be considered. 

 The glandular lobe (pi. 3, fig. 18) is, as has been said, much the 

 largest region of the hypophysis. It consists of indefinite cords or 

 strands of cells, between which are very numerous blood capillaries 

 (ca) in most of which blood corpuscles (be) may be seen. 



The cells are of two, possibly three types, as judged by their 

 nuclei. The cell boundaries are seen with the greatest difficulty, if 

 at all, in sections stained with haematoxylin and eosin. 



The most abundant type of cell (/) is spherical or polygonal and 

 is characterized by a very large, usually spherical nucleus, in which 

 are fine granules and often one or two larger granules or nucleoli. 

 The nuclear granules do not stain so darkly as those in the next type 

 of cells. The cytoplasm of these cells sometimes stains very faintly 

 in eosin, but not a deep pink, like the adjacent red blood corpuscles. 

 Possibly they correspond to the oxyphil cells of the human pituitary. 



The second type of cell {2) is characterized by its small, darkly- 

 staining nucleus. It is not quite so numerous as the former cells. The 

 nuclei are much smaller than those of type i, and are pear-shaped or 

 triangular in outline. Owing to their dark staining and characteristic 

 shape they stand out in sharp contrast to the nuclei of type /. 



Besides these two, a possible third type is shown (j) though these 

 cells may be merely a variation of one of the preceding types. The 

 nuclei are of intermediate size and are spherical or oval in shape. 



An occasional vesicle with inclosed colloid (co) may be seen. 

 The wall of the vesicle seems to be made up chiefly of cells of the 

 smaller sizes, with an occasional cell of type /. Around the lobe is a 

 connective tissue capsule (c) a part of the meninges of the brain. 



A high-power drawing of a small region of the middle lobe and the 

 adjacent nervous lobe is shown in figure 19 (pi. 3). This region 

 differs from the main or glandular lobe in being much less vascular 

 and in being made up almost entirely of only one, or possibly two, 

 kinds of cells. Most of the cells shown in the figure are those con- 

 taining the very large, round nuclei. These nuclei seem to stain 

 darker than the corresponding nuclei of the glandular region. The 

 cell outlines are more evident, in some cases, than in the glandular 

 region. Only a few of the small, round nuclei are seen and still fewer 

 of the pear-shaped ones that were so much in evidence in the glan- 

 dular lobe. 



