No. 1.] EPITHELIUM OF MUSTELVUS CANIS. 69 
different heights either above or opposite the nucleus. It was 
never found proximal to the nucleus in the cylindrical cells. 
The nerves end in a single rounded end plate proximal to 
the nucleus in the rod cells. 
The third kind of ending was found in connection with cells 
which do not reach the surface and in which the nucleus is 
placed at right angles to the long axis of the cell. 
Bethe does not think that the blue coloration of the cell is 
any indication of its sensory nature, as he found quite a variety 
of cells stained in that way; the color was superficial. 
He found nerves ending in connection with gland cells, 
ciliated epithelial cells, and in deep epithelium cells distin- 
guished by dark nuclei. 
On the ciliated cells the clover-leaf-shaped end plate was 
found in contact with the cell. Frequently a small branch of 
the nerve extends to the surface and ends free without a 
terminal enlargement. 
The dark nucleated cell with the round end plate is sparsely 
scattered through the epithelium. 
Bethe has seen varicosities form on the slide in living nerve 
tissue of the crayfish, and considers those seen in nerve 
preparations as artifacts. 
II. Methods. 
In recent study of the auditory epithelium, embryonic mate- 
rial has been treated by the rapid Golgi method, and adult 
tissue with Ehrlich’s method. 
In my investigation of the auditory epithelium of adult 
Mustelus, I was unable to secure any results with Golgi’s 
method, although many experiments were tried. 
At first Ehrlich’s method gave widely different results, but 
after considerable experimentation it was found that by using 
only active, healthy fish killed by decapitation as soon as 
removed from the water, it was possible to secure uniformly 
good results by using certain precautions. 
The ampullae were removed immediately and placed in 
enough normal salt solution to cover them. A Minot solid 
