DEVELOPMENT OF THE HYPOPHYSIS 427 
Fig. 29 Transverse section of a gland of the inferior lobe of anadult. X 400. 
b. Inferior lobes. The inferior lobes are large glandular struc- 
tures, from the walls of which are many tubular outgrowths. 
These tubules are especially numerous on the ventral surfaces 
of the inferior lobes although there are some on the roof also. 
Two or three layers of columnar cells form the walls. In this 
case a wider cytoplasmic zone lies along the inner free surface 
(fig. 29). The cytoplasm is clear and the cell membranes stand 
out distinctly. The cells are very faintly acidophile. The 
nuclei here, as in the anterior lobe, are oval in outline, and the 
long axis is always at right angles to the free surfaces. The 
chromatin here also is in a fine network with a more or less 
definite layer along the nuclear membrane. 
c. Superior lobe. As has been observed in all selachians, there 
is a great glandular outgrowth from the roof of the superior lobe. 
As Sterzi has noted, these glands are not tubular but solid. 
The floor of this portion shows no glandular outgrowth. It is 
made up of several layers of columnar cells. The roof is several 
cell-layers deep and from it many thick columns extend upward. 
