972 
large cells of the anterior horn, which has meanwhile grown much 
shorter, have united into an oval-sbaped complex which is surrounded 
by a fibre system. At the calamus a few cells have left the complex 
and now le under the lateral point of the newly opened central 
canal (fig. 3). Somewhat frontally from the calamus no traces of 
similar XII cells are to be seen, but they very speedily reappear 
and in a few sections the direct connection between the tongue 
nucleus and the cervieal anterior horn gray matter is quite plain 
(fig. 4). There are then 12—18 large XII cells to be seen laterally 
under the base of the [V ventricle, under that the remains of the anterior 
horn still well developed and clearly defined, and between are the 
connecting cells. The separation of tongue nucleus from the cervical 
gray matter is evidently difficult, for about 100 sections frontally 
from the calamus a small group of anterior horn cells can still be 
observed ventrally from XII, 
The cells in this group are larger than XII. cells, and the group 
also shows distinct remains of the surrounding fibre-system (fig. 5). 
Even when it has broken up, distinct anterior horn cells are still found 
in the immediate neighbourhood of the ventral pole of nucleus XII. 
A remarkable phenomenon presents itself here. Laterally from the 
anterior horn rest a cell group oecurs, which develops in the 
direction of the nucleus motorius dorsalis vagi. It varies in strength 
and exhibits the cell type of the tongue nucleus; sometimes we see 
28 cells. In several 
a few cells and again an elongated group of 25 
groups there is an actual bridge between the rest of anterior horn 
and vagus nucleus (fig. 5). 
As regards the development of the tongue nucleus itself, we see 
the medial portion appear first, in the angle between the ventricle 
base and the fase. long. posterior. As long as the rest of the ante- 
rior horn is still present, this group is well developed; it is rather 
crowded and contains cells which are but slightly smaller than the 
anterior horn cells. This medial group grows out in a lateral direction 
under the ependyma and simultaneously some cells of a smaller type 
belonging to the ventral group make their appearance ; they can be 
easily recognised owing to the remarkable difference in size from 
the few front horn cells still present in their immediate vicinity. 
Very soon the ventral pole strengthens and then forms a whole with 
the cell group which has already developed in a dorsolateral direction 
to such a degree as to form a direct connection at that place 
between the cervical grey matter and X. dorsalis. In the same 
preparations we see that cells of smaller type have appeared between 
ihe lateral portion of the tongue nucleus and the adjacent vagus 
