92 GEORGE W. BARTELMEZ 
ner’s cells which are visible to the naked eye. The cells lie for 
the most part lateral and ventral to the fasciculi longitudinales 
medialis et lateralis, their dendrites extending to the periphery of 
the oblongata as is indicated on the left side of figure 4. The 
receptive field of the rostral end of the nucleus is, therefore, the 
whole area between the mid-line and the Vth and VIIth motor — 
nuclei (figs. 3-4), while caudally it lies between mid-line and nu- 
cleus lateralis tegmenti (fig. 5). Golgi preparations show a dense 
neuropil in this region made up of the dendrites of the cells of the 
nucleus, collaterals from the primary sensory bulbar nuclei and 
from the long descending paths of the oblongata. The axones 
from the cells of the nucleus make up the greater part of the 
fasciculus longitudinalis medialis; the great majority of them de- 
scend in it, a few ascend, and some bifureate into a large descend- 
ing and small ascending ramus. 
It is with the large cells that we are chiefly concerned. Their 
general relations and position in the cross section are indicated in 
figure 4 where they are seen to have large cell bodies and usually 
- two dendrites, sometimes only one, directed ventro-laterally and 
branching in the neuropil near the periphery. The axone arises 
dorsally and turns into the fasciculus longitudinalis medialis. The 
Nissl substance (fig. 9) is in the form of discrete bodies, which, 
however, are not so large or regular in outline as they are in 
typical motor cells. 
The other cells of the nucleus are either commissural or Golgi 
type II cells or belong to the short path (i.e., formatio reticularis) 
type. While the latter types form a continuous column, the 
large cells are arranged in groups which correspond to the distinct 
subdivisions of the nucleus found in larvae. At the level of these 
groups we find the dense neuropil and here the small cells are 
more numerous than elsewhere and extend farther laterally, so 
the groups are indicated in the reconstruction (fig. 2) by enlarge- 
ments. 
It will be seen in figure 2 that the nucleus is larger throughout 
the region of the primary VIIIth centers (N.ac.vent. and N.ac.- 
dors.) and that its four rostral groups which are coextensive with 
the height of the secondary acoustico-lateral decussation show 
