1125 
tion of the accessorius nucleus. The rad. descend. V is, however, 
more developed in the oblongata, and its ventral border comes to 
lie in a much lower region. Ambiguus and accessorius nucleus are 
both derivatives of the dorsal motory vagus nucleus. This has been 
proved phylogenetically and ontogenetically by Karpers, and is again 
confirmed in the camel by the intermediate cells between the dorsal 
motor X nucleus and the nucleus XI and the simultaneous but 
distinctly separate presence of the latter and the nucleus ambiguus 
on the same transverse level. 
The nucleus ambiguus of the camel is, with the exception of its 
frontal pole, but slightly developed. In the closed part of the oblon- 
gata it shows no more than 10 to J2 cells in one section and very 
frequently none at all are to be found. This holds good also for 
the rest, with the exception, as said above, of the frontal pole. On 
a transverse level corresponding with the frontal end of nucleus XII, 
we still find clusters of 4—6 large ambiguus cells, while on the other 
hand, on the level corresponding with the frontal pole of the dorsal! 
motor vagus nucleus, the nucleus ambiguus enlarges very rapidly to 
an immense compiex of cells in which a maximum of 80—85 cells 
5 - os eral = es ~ . 
A tre Ch af r ” v 
é = mr Sit Sw er 5 ¥ 
+ - De = 
rn. Wes CK B von 
: *t . ed En v Pid 
“ Pi , - a 
fees Laus Fie g 
Racy darBdymmnd: o° ~ 
ages Frontal enlargement 
; a of the nucleus ambi- 
x guus in the camel. 
Fig. 8. 
Showing the separate character of the nucleus 
accessorius and nucleus ambiguus. 
may be counted. Frontally the enlarged nucleus ambiguus can be 
divided into a medial portion with smaller and a lateral portion with 
larger cells. While the frontal enlargement of the ambiguus (where 
it occurs) is generally described as a mass of closely crowded cells 
of smaller type than the ordinary ambiguus cells, it is here remark- 
able that the cell group is not so crowded together and contains, 
especially in the lateral portion, typically large ambiguus cells (fig. 9). 
Its frontal extremity has clearly shifted ventrally. Lt is 54 sections 
long and extends 30 sections frontally from the dorsal motor vagus 
nucleus (fig. 6). Twelve sections further the nueleus VII begins. 
Coneerning the Aypoglossus nucleus it may be mentioned that its 
