NOs Te] EPITAELEACE ORVMUSTELUS: CANIS. 65 
nerve fibers extending so near the surface as Retzius (93), 
Kaiser ('91), Niemack (92), and Geberg ('92), but thinks the 
difference between his results and those of Retzius may be due 
to the age of the embryos studied. At the point of division or 
separation of the nerve fibers he observed the characteristic tri- 
angular thickening, and says that the nerve fibers were of nearly 
equal size. He did not find the wide-meshed network of nerves 
described by Niemack as existing at the base of the auditory 
epithelium of the frog and rabbit. The horizontal nerve fibers 
at the base of the hair cells were generally toothed on their 
upper surface, mainly at points where branches arise. He did 
not find any free endings at the surface and questioned the 
value of Niemack’s sections, in which fibers were traced to the 
surface. Nothing was observed to support Kaiser’s view. 
The nerve fibers which did not end free terminated in thick- 
ened knobs in contact with the surface of the hair cells. No 
more than two or three branches were observed to end in con- 
tact with a single hair cell. The number of nerve fibers was 
so great that their relations could only be studied when isolated 
nerves and their branches were stained. Lenhossék calls 
attention to the fact that it is easy for an inexperienced 
observer to be deceived when many nerves are stained, and to 
be led to think that anastomoses exist. In thick sections the 
tangle of fine varicose horizontal fibers and their cut branches 
at the base of the hair cells may easily be taken for a granular 
mass. This is, he thinks, the granular substance described by 
Kaiser and Niemack. Three layers are described in the mac- 
ulae and cristae acusticae: (1) a hair-cell zone in which there 
are two layers of crowded cells arranged perpendicularly to the 
surface ; (2) the nerves forming a “ plexiform stratum”’ at the 
base of the hair cells; (3) the supporting-cell zone with the cells 
placed vertically. 
On the basis of the fact that in his preparations the nerves 
never extended to the surface, he concludes that the hair cells 
are the medium through which the movements of the endo- 
lymph are conducted to the nerve fibers. He does not think 
that there is any intermediate substance connecting the nerves 
and hair cells, but that the peripheral portion of the cell pos- 
