178 J. B. JOHNSTON, 
however, Kinaspury found the caudal limit of the fasciculus com- 
munis not easy to determine. 
The description of the caudal portion of the lobus vagi in 
Acipenser given above (page 83) differs from my previous description 
(98b) in that I have worked out the nucleus of the commissure 
and the cervical bundle since the preliminary communication was 
published. I got the first satisfactory results in this region by the 
study of the brain of Amia, Teleosts, and the frog and I shall give 
in their proper sequence in the following pages the results of these 
comparative studies. In a series of frontal sections of an adult 
Amia brain I find that in haematoxylin sections through the com- 
missura infima Halleri the fasciculus communis appears to be in 
connection with both the dorsal horn and the central grey matter. 
It may be that the commissure contains decussating fibres from 
other sources than the lobus vagi, as suggested by Mayser. I 
have seen some indication in GOLGI sections in Acipenser that fibres 
from the nucleus funiculi may cross here. Caudad from the com- 
missure the communis system continues as paired fibre bundles ac- 
companied by cells, imbedded as a whole within the dorsal raphe 
of connective tissue and quite separate from the dorsal horns or 
tracts. These bundles and cells gradually disappear. 
I have also examined Teleost 
embryos (Coregonus and Cato- 
stomus) sectioned in the three 
planes and stained with the EHr- 
LICH-BIONDI triple stain. The 
following features of the fasci- 
culus communis were common 
to both genera. The lobus vagi 
appears distinctly divided into a 
cell layer adjoining the central 
i BA. cavity and a fibre layer lateral 
to it (Fig. V). Cells and fibres 
are sharply differentiated, the 
cells (nuclei) being stained green 
and the fibres red. The com- 
missura infima H. is easily made 
out in Coregonus and is very strong in Catostomus. At the level of 
the commissure the fibre layer is apparently in communication with 
the acusticum and the nucleus funiculi. This is due at least in part 
-IVven 
en oh i 
