971 
commenced. Very soon this consists of a complex of 75 rather 
scattered cells which increase in number, after which the nucleus 
here too frequently divides into two groups, a lateral one and a 
medial one. The lateral group contains the largest number of cells 
and the cell type is larger than that of the medial group. This 
medial group is of varying size, diminishes, sometimes disappears, to 
reappear again and increase. We can Clearly see cells from the lateral 
group entering a more ventral level. The medial group disappears 
for good, the lateral one decreases rapidly, and then gradually 
becomes larger again. On a closer examination, however, it will 
appear to have then reached the facialis region. 
In Phocaena the ambiguus passes directly into the nucleus facialis 
The frontal pole of the ambiguus in this animal may be considered 
to extend in this series about 90 sections frontally from the nucleus 
motorius dorsalis vagi (fig. 7). 
NW LLLLITIL TTT TTT TT TI ITD 
YA 
Fig. 7. Phocaena communis. 
EXPLANATION OF THE MARKS: 
“te arene). : E = 
) =calamus, (43) = oliva inferior, WH = Nucl. IX, gm= Nucl. X, 
Ne E 2 ne If : 
N= = Nucl- XI, gg = Nucl. XII + Cervicale I, if = connection between 
X dorsalis and X ventralis, = Nucl. VII. 
Nucleus hypoglossi. The direct transition of the motor cervical 
column into the tongue nucleus is very distinctly seen in Phocaena 
(fig. 4 and 7). In the vicinity of the calamus we see that the 
