( 1061 ) 
Which eaanot be sharply defined from each other. Even the collection 
of the giant-cells of the oetavus and of the rather more caudal region 
into a separate nucleus, although these cells are clearly larger than 
the largest reticular cells which occur in the vagus-hypoglossus region, 
seems to me to be undesirable at the present time. The transition 
in the size of the cells is after all a gradual one, and whether here, 
as in birds, by reason of a different course of the axis-cylinders, the 
cells of the vagus region of the oblongata have to be distinguished 
from those of the octavus region or not must be decided by further 
histological research. 
By my method of research I could not make distinctions based 
on cell-structure differences between the cells; I must therefore 
refrain from passing an opinion. ©) 
If we collect all the reticular cells of the caudal half of the oblon- 
gata — calculated to about the frontal boundary of the VIIL root- 
entrance -— into one nucleus, we might term this nucleus reticularis 
mferior, and to indicate that the cells extend to the raphe and partly 
collect there, we might distinguish a pars raphes and a pars lateralis; 
and possibly also include the ne. reticularis funiculi lateralis. 
On a level slightly frontal from the VIII root-entrance the number 
of reticular cells decreases, to increase again on the level of the 
V nucleus. On the level of the motor V nucleus and in more frontal 
parts of the oblongata | no longer found any giant cells in the 
raphe except sometimes (Macropus) a very few on the level of the 
most caudal part of the mot. V nucleus. Cells are indeed found in 
the raphe which agree with the ne. pontis and still further frontally, 
immediately behind the corpora quadrigemina, a raphe nucleus of 
small cells. To these cells, which have probably another origin and 
meaning, IT shall return later. 
The large reticular cells in the oblongata of the trigeminal and 
praetrigeminal regions of the mammals, with the exception of phocaena, 
showed a peculiarity in their arrangement which was not equally 
conspicuous in all. The cells are divided more or less clearly into 
two groups, one of which remains lying more dorsally in the bulb 
While the other has shifted in a ventro-lateral direction, coming to 
') The large reticular cells which occur in man on the caudal part of the VIII 
root-entrance, are counted by Jacossoun as belonging to two reticular nuclei, which 
lie partially through each other: his nc. giganto cellularis formationis reticularis 
and his nc. motorius dissipatus formationis reticularis. This distinction he makes 
solely on the ground of cell-structure differences, while he states that the cells of 
the ne, not, dissip. fr. are in general smaller than those of the ve. gid. fins 
although they sometimes attain the size of the latter. 
