MUSEUM OF COMPARATIVE ZOOLOGY. 119 
the slime by which the young “ gars ” are thickly covered. They are 
not, however, the only agents concerned in its production. 
The epidermal glands of the second kind are considerably smaller 
than those already described ; they are nearly spherical, and have an 
average diameter of from 18 to 25 p. They do not appear to have been 
recognized by previous observers. Some of these lie in the deeper 
part of the epidermis, but much the greater number and the larger ones 
occur near the surface, where many of them open. 
They stain deeply with Kleinenberg’s and with Delafield’s hema- 
toxylin, but in all other stains used, even in other hematoxylin dyes, the 
nuclei alone are colored, and in this condition they can be distinguished 
from small glands of the first kind only by very careful observation. 
This probably accounts for their having been overlooked heretofore. In 
Kleinenberg’s hematoxylin the whole gland takes a blue tint, while the 
wall presents a reticulated appearance due to an irregular network of 
lines of a much deeper blue color. This appearance is shown in Figure 
2, a-e. The glands lying in the deeper part of the epidermis (d) take 
less color than those situated just below the surface (c); those which 
open at the surface vary much in the intensity of their coloring, the 
differences doubtless being due to the varying amounts of mucin con- 
tained in them. The distribution and peculiar staining qualities of 
these glands show that they originate in the deeper part of the epidermis 
and migrate to the surface, where their secretion is discharged. 
Hematoxylin has long been known to stain mucus deeply. Hoyer 
(90) found that basic stains are those which chiefly affect mucin, and 
that hematoxylin stains which contain alum act like basic stains. Of 
the four hematoxylin dyes which I have used, Kleinenberg’s (basic) and 
Delafield’s (alum) gave characteristic deep blue stains to these glands; 
Boehmer’s (alum) and Ehrlich’s (acid), on the other hand, gave pure 
nuclear stains. Hoyer imputed certain failures of hematoxylin stains 
to act in their normal manner to lack of “ripeness,” and it is possible 
that this may be the reason for Boehmer’s alum hematoxylin not col- 
oring the mucin in this case. 
At all events, I believe that the stains which I have obtained afford 
sufficient ground for declaring that these cells act as glands, and secrete 
the mucin element of the slime by which the young gar-pikes are thickly 
covered. The other and larger glands first described, which take only a 
nuclear stain with Kleinenberg’s hematoxylin, must be considered to 
have the function of secreting some component of slime other than 
mucin. 
