THE HYPOPHYSIS IN REPTILES 259 



face. Some of the cells (eosin-methylene blue) are filled with 

 large blue-staining granules, others with bluish-tinted homo- 

 geneous masses, which lie partly in the lumen. In the lumen, 

 also, are large round vacuolated cells and a small amount of blue- 

 staining reticular substance. The spherical nuclei stain homo- 

 geneously or show one or two large chromatin masses. 



Snakes 



In adult garter snakes and adders the pars intermedia, which 

 almost surrounds the infundibular outgrowth, is formed of a 

 thick layer of cells which occasionally dip into the infundibulum. 

 On the outer surface is a very narrow cytoplasmic zone which 

 takes eosin very lightly. Cell membranes are indistinct. The 

 nuclei are spherical, with a light chromatin network. 



The anterior lobe, as in Sceloporus, is formed of columns or 

 cords which have an outer, narrow, finely-granular rim of cyto- 

 plasm in which some cells stain a brilliant red with eosin. Be- 

 cause of the differential staining, it can be seen that the cells 

 are columnar or polyhedral in shape, although cell membranes 

 are not well defined. There are two or three rows of centrally- 

 placed, spherical or oval, light-staining nuclei, usually contain- 

 ing one nucleolus. Many bluish-staining masses, about as large 

 as the nucleoli, are found in some of the reddish-tinted cells. 



Alligators 



A specimen about 150 cm. in length, fixed in Zenker-formalin, 

 proved to be the best for histologic study. This animal was 

 received in December and kept in a tank for a few days during 

 which time he was frequently disturbed. The sections varied 

 in thickness from 5 to 10 micra and various stains were used. 



The pars intermedia is relatively thicker than in smaller speci- 

 mens. Caudally, the cells are arranged in lamellae which branch 

 anteriorly into irregular cords and completely surround all 

 branches of the infundibulum. The cells are irregular in shape 

 and there is a definite outer zone of cytoplasm. The cytoplasm 

 of centrally-placed nuclei extend between peripheral cells to the 



