MAUTHNER’S CELL 109 
such appearances in the vertebrate central nervous system only 
in glial elements. 
4. The nucleus frequently shows two chromatin nucleoli and 
in many cells there are evidences of amitosis (e.g., Gl.a., Gl.b., 
Gl.c., Gl.d. of figure 12). 
5. The structures shown at Gl.b. in figure 11 were abundant 
in this preparation and were interpreted as neuroglia fibers. 
Some experiments with specific neuroglia stains were not success- 
ful, however. 
The pericellular net or basket (‘canestro’), of Mauthner’s cell 
forms a thick dense sheath for cell body, dendrites and axone. 
It has been admirably described and figured by Beccari (’07) and 
I have nothing further to add except certain additional types of 
fibers which are included in the following summary. 
Mauthner’s cell is, as Beccari and Tello have pointed out, a 
nucleus in itself, for the associated groups of the nucleus motorius 
tegmenti have not all the connections which it has. We can 
determine definitely how many different kinds of impulses may 
reach a single nerve cell in this case, and as the sequel shows the 
number is surprising. 
1. Vestibular root fibers: (a) Homolateral fibers ending upon 
the lateral dendrite. (b) Homolateral fibers giving off collater- 
als to the axone cap. ‘(c) Contralateral fibers giving off collat- 
erals to the axone cap and pericellular net. 
2. External and internal arcuate fibers from the ventral acous- 
tic nucleus to the pericellular net of the inferior ventral dendrite. 
_ 3. Axones and collaterals from the dorsal acoustico-lateral nu- 
cleus: (a) Collateral endings in the axone cap from decussating 
fibers crossed and uncrossed. (b) Endings of collaterals and 
axones in the pericellular net. (c) Collaterals from lower levels 
of the dorsal nuclei via the fasciculus longitudinalis lateralis to the 
‘pericellular net. 
4. Fibers from the fasciculus longitudinalis medialis: (a) End- 
ings in the axone cap from the mesencephalon. (b) Collaterals 
from the ventral bundles of the tract to the pericellular net and 
the axone cap, mostly uncrossed. 
