260 E. A. BAUMGARTNER 



surface of the column. Thus the appearance is that of a pseudo- 

 stratified columnar epithelium in which all cells come to the 

 periphery. The cytoplasm at the center of the columns fre- 

 quently appears vacuolated and shrunken around the nuclei, 

 leaving irregular spaces. This cytoplasm stains lightly with 

 eosin or orange G. Occasional small areas, the peripheral parts 

 of some cells, stain more intensely. Small, round, homogene- 

 ously-staining masses, varying in size, are found grouped or 

 isolated near the surface of the columns. A reticular network 

 of the cytoplasm is often prominent. The spherical nuclei stain 

 lightly except for a densely-staining nucleolus. There are from 

 two to seven irregular layers of nuclei in the columns, some lying 

 near the basal membrane. 



The structure and arrangement of the pars tuberalis is more 

 discernible in the large alligator than in the turtles. The con- 

 dition of the individual animal may have a bearing upon this 

 point. The two parts of the pars tuberalis lie in such proximity 

 in the 150 cm. specimen, that they may be said to fuse, although 

 they are distinctly separated in the smaller adults. The pars 

 tuberalis is composed of irregular columns of cells separated by 

 a large amount of vascular connective tissue. The columns are 

 formed of clear, vacuolated, non-granular, polyhedral cells with 

 a reticular network. The borders of the columns occasionally 

 stain intensely. Cell walls are usually distinct. The nuclei — 

 round, oval, or irregular in outline — do not stain deeply, except 

 for a distinct membrane and for one, sometimes two or more, 

 small densely-staining nucleoli. 



The proximal parts of the lateral lobes, forming bands encir- 

 cling the anterior lobe, are composed of columns. These are 

 somewhat smaller, more irregular, possible less vascular than 

 those of the pars tuberalis and are separated by a thin connective 

 tissue layer. The histologic structure is like that of the pars 

 tuberalis, although there are tubules running through ten or 

 more sections and ending blindly. The tubules are lined with 

 columnar epithelium with basal nuclei. Cell membranes can 

 be seen. Both the cytoplasm and nuclei stain more densely 

 than in the surrounding cords and columns. A reticular sub- 



