96 GEORGE W. BARTELMEZ 
dition is doubtless correlated with the fact that the fasiculus lon- 
gitudinalis lateralis (lemniscus) and the tecto-bulbar tracts are 
converging toward their end and origin respectively at these 
levels. Most of the cells of the pars superior are of the same 
size as those of the pars premauthnerea but six or seven are as 
large as the Miller cells of that group. Figures 8 and 9 show 
four cells of this group. There are, however, at the caudal end 
of the pars suprema nine or ten cells which, in the size of cell 
body and girth of dendrite surpass any other cells of the whole 
nucleus except the Mauthner cells themselves. They are as 
large as the Miiller cells of this level (fig. 2) and are apparently 
homologous with Tello’s ‘nucleo motor tegmental anterior interno.’ 
Every axone from this group descends in the dorsal part of the 
fasciculus longitudinalis, medialis and constitutes the second link 
in the direct cerebello-spinal system. The tractus cerebello-teg- 
mentalis-bulbi of Edinger (08) and Franz (’11) and others does 
not extend throughout the bulbar tegmentum, so far as my ob- 
servations go, but ends chiefly in the pars suprema and to a lesser 
extent in the pars superior nuclei motorii tegmenti. 
To summarize the connections of the nucleus motorius teg- 
menti bulbi we may say: 
1. The axones run in the fasciculus longitudinalis medialis, 
crossed and uncrossed, and most of them descend but some bifur- 
cate into ascending and descending branches. A bundle of the 
largest accompanies Mauthner’s fiber through the spinal cord. 
2. The cell groupings are determined, in part at least, by the 
primitive relation to the somatic motor (III, IV, VI, spinal) and 
specialized visceral motor (V, VII, IX, X) nuclei, whose activi- 
ties are codrdinated by means of this nucleus and its tract, the 
fasciculus longitudinalis medialis. 
3. All parts of the nucleus receive collaterals from the fascicu- 
lus longitudinalis medialis, the fasciculus longitudinalis lateralis 
and the tecto-bulbar system. . 
4. The caudal half receives collaterals from the tracts arising 
in the primary sensory nuclei of the Xth, VIIth and Vth nerves 
and to a lesser extent in the acoustico-lateral nuclei. The rostral 
half is very closely related to the acoustico-lateral system and to 
