108 GEORGE W. BARTELMEZ 
last type of fiber gives reason to believe that the axone cap has - 
developed pari passu with the great lateral dendrite and both 
are expressions of the intimate relation of this nucleus motorius 
tegmenti cell with the VIIIth nerve; hence Mauthner’s cell is 
the only one which has them. 
b. The cap dendrites. In figure 10 certain processes are shown 
extending from the body of Mauthner’s cell across the shrinkage 
space in this region toward the axone cap. They can be recog- 
nized in most good Cajal preparations but judging from them 
alone they might well be considered artefacts. In formol-Zenker 
material the picture is clearer (figs. 6-7) and after formol-osmic- 
Zenker fixation their true nature can be best appreciated. Thus, 
in figures 11 and 12 they are seen to be delicate dendrites extend- 
ing through or ramifying in the cap. There may be as many as 
eight of them, but for the sake of clearness most are omitted 
from figure 11, which represents a drawing of several superim- 
posed sections. These dendrites obviously increase the receptive 
field in the region of the axone cap and they receive impulses 
from the felted collaterals, whereas the knob endings (figs. 10 
and 12, K.End.) transmit impulses directly to the cell body. 
C. Supporting elements. There is no evidence that, as Mayser 
supposed, ependymal fibers enter the axone cap but there are 
supporting elements in it. In figure 11 scattered cells are shown 
at the surface of the cap (Gl.a.) and a similar cell (Gl.b.) nearby 
sends out two delicate fibers toward it. These cells are more 
clearly seen at a higher magnification in figure 12; here they ap- 
pear as stellate elements sending processes into the cap and the 
surrounding neuropil (cf. Gl.c.). I have interpreted them as neu- 
roglia cells for the following reasons: 
1. They show no evidence of Nissl substance even in the adult, 
where the cytoplasm is frequently well preserved. 
2. Preparations which show excellent preservation of all nerve 
cells have some of these cells very poorly fixed. Huber mentions 
this as a feature of the glia cells of the frog and it appears in fig- 
ure 11. 
3. The cells anastomose with one another, as may be seen in 
the case of the cell Gl.b. and its neighbor in figure 12. We find 
