430 E. A. BAUMGARTNER 
pophysis) as composed of three layers, of which the middle was 
made up of nerve fibers coming from the caudal end of the inferior 
lobes of the brain. When these fibers reach the area above the 
superior lobe, numerous bundles of them go ventrally between the 
columns. These bundles are large and composed of large nerve 
fibers. According to Stendell (12) a distinct lumen, continu- 
ous with the lumen of the vascular sac, extends into these bun- 
dles in Heptanchus. As Sterzi (’09) showed, these bundles are 
solid in Acanthias. Sterzi was not able to see any of the fibers 
ending in the cell columns. In some material stained with 
Mallory’s phosphotungstic acid hematoxylin these fibers are 
well shown. I can not affirm that they do end in the cell 
columns between the cells as Sterzi was inclined to believe. 
e. Secretions. Haller (’96) stated that the lumina of the 
superior lobe may contain cell detritus or a secretion. Tilney 
(11) observed a colloid-like substance in the vascular sac above 
the superior lobe. Stendell (713) described deep acidophilic 
secretion granules in the cytoplasm of the cells of the ‘Zwischen- 
lappen.’ These colloid-like secretions were found in the cells 
lying towards the blood vessels. The adult Acanthias studied 
show no colloid-like secretion granules, such as Stendell found 
in the cytoplasm near the sinusoids in Mustelus and Seyllium. 
Considefable colloid-like secretion, however, is found in the 
tubules of the anterior lobe, also some in the main lumen of this 
part. The tubule drawn in figure 28 contains secretion. Some 
secretion was found in the tubular glands and in the main lumen 
of the inferior lobes. There are also many spaces in the superior 
lobe which are partially filled with secretion. The spaces are 
cylindrical in shape, sometimes as much as 20y in diameter and 
50 to 200u long. They have no special walls, the cells and nuclei 
lining them appear to have been crowded aside. Frequently 
the inner layer of nuclei lies flat along the wall. These spaces 
never come in contact with the sinusoids, but are always found 
in the middle of the columns and are surrounded by nuclei which 
are crowded close together. Aresu (14) has described similar 
cyst-like spaces in Chimaera, containing a substance which stains 
lightly with basic stains. That the secretion does not fill the 
