434 E. A. BAUMGARTNER 
b. Inferior lobes. 'The development of the inferior lobes as 
constrictions of the lateral walls of the early hypophyseal out- 
pouching has been described above. The point where these 
lobes will grow together across the median line is indicated in 
figures 5 to 10. The character of the cells forming this part differs 
from the rest of the hypophyseal outpouching as early as the 
21 mm. stage (fig. 32). The cytoplasm here stains less densely 
than that of the rest of the hypophysis. The nuclei are distinctly 
spherical in shape and have a very scant chromatin network. 
A part of this floor, immediately posterior to the hypophyseal 
stalk, contains a considerable amount of a granular yellowish 
pigment. Both Miller (71) and Hoffmann (’96) have noted the 
Fig. 34 Sagittal section of the floor of the hypophysis near the median plane, 
showing the part which connects the inferior lobes. (H.E.C. 362). 400. 
pigment in the stalk of the hypophysis. The nuclei become more 
oval in older embryos. This is well shown in figure 34 which is 
a mid-sagittal section of the region which later forms the con- 
nection between the inferior sacs. The nuclei here are very 
irregularly placed. Extending caudally from the stalk are several 
nuclei flattened along the inner free surface. The cytoplasm 
stains very lightly. The pigment masses are- numerous. Cau- 
dally there is a sudden transition to columnar cells of. the kind 
found in the wall of the anterior lobe. The floor in this region 
is as just described until the 48 to 50 mm. stages when the infe- 
rior sacs are completely constricted from the anterior one. ‘The 
pigment and the flattened nuclei are found only near the median 
line. Both are still present in a 41 mm. embryo. 
In the inferior sacs proper, however, which are formed at the 
lateral sides, the cells are similar to those of the floor of the 
anterior lobe. The outer, narrower zone of cytoplasm, as well 
