242 DAVIDSON BLACK 
nucleus. Over the greater portion of its extent it is intimately 
associated with the cells of the nucleus intermedius XII, the 
two nuclei forming a complex (fig. 2), the limits of whose com- 
ponent parts may, however, be distinguished by the course and 
distribution of their respective root fibers. In contrast to Ca- 
catua, the cross-sectional area of the nucleus intermedius complex 
(combined X—XII components) in Ciconia is at all levels less 
than that of the adjacent dorsal motor vagus nucleus. The 
nucleus intermedius X is somewhat more extensive than the 
nucleus intermedius XII, so that it overlaps the latter nucleus 
both rostrally and caudally. In transverse sections of the brain 
stem at these levels the nucleus intermedius is formed wholly of 
motor vagus cells. 
A ventro-lateral motor vagus nucleus may be clearly distin- 
guished in Ciconia occupying a position analogous to that of the 
similarly named nucleus in Cacatua. As in the latter form, its 
rostral and caudal limits could not be accurately defined, though 
the position of its chief cell mass is indicated in the reconstruc- 
tion chart, figure 16 C, page 260. 
It is evident that the same grouping of avian forms will result 
from an arrangement on the basis of the vagal connections of 
the nucleus intermedius as on the basis of the central origin of the 
hypoglossal nerve. Thus, group I, as noted above, contains 
those forms in which the nucleus intermedius is largely vagal; 
group II is composed of forms in which the vagal and hypoglossal 
components of the nucleus intermedius are both quite evident, 
and group III consists of those forms in which the nucleus inter- 
medius is to a very large extent a hypoglossal nucleus. 
Nerve VII 
The motor VII nerve in Cacatua has its origin within the 
brain stem from two distinct cell groups, which from their 
relative positions are termed, respectively, the dorsal and the 
ventral motor facial nuclei.7 
7 These nuclei were first charted and fully described by Kappers (82), though 
this author noted at the time (l.c., p. 69) that two such nuclei had been observed 
