oa 
The brain of Acipenser. Wen 
3) Lobus vagi. 
MAYSER (81) indicates the general relations of the lobus vagi 
as follows: “Subst. gelat. Rolando des Riickenmarks, Lobi vagi und 
Lobus trigemini hängen continuirlich mit einander zusammen und 
haben auch denselben histologischen Bau. . . .. Zwischen den Lobi 
vagi et trigemini einerseits und den Hörhöckern andrerseits besteht 
keine Gewebscontinuität, vielmehr sind sie durch Bindegewebe und 
die austretenden Nervenwurzeln von einander getrennt.” The lobi 
vagi et trigemini of MAYSER are now recognized by all authors as 
one body under the name of lobus vagi, the cephalic part of which 
is greatly enlarged in some fishes and has been known by the 
names lobus trigemini and lobus impar. The entire separation of 
this from the tuberculum acusticum which MAYSER points out has 
not been held in mind by all authors. I have insisted on it (98b) 
and have shown (page 83 ff., above) that there is not only no con- 
tinuity of tissue but the widest difference in structure between the 
two bodies. The inadequacy of the old methods has led MAYsEr 
into error in connecting the substantia gelatinosa with the lobus 
vagi. I have shown that in Acipenser these nuclei are separated by 
connective tissue, that their structure is different, and that the sub- 
stantia gelatinosa is connected with the acusticum. MAyYSER’s de- 
scription of the secondary vagus tract in the carp and its relation 
to the spinal V have been discussed above (page 165). 
I have already commented upon VAN GEHUCHTENS description 
of what he calls the “descending root of the IX and X” (page 167). 
KINGSBURY (97) gives the results of macroscopic examination 
and the study of histological sections of the brains of several 
Ganoids and Teleosts. This author has cleared up certain incon- 
sistencies and errors of the earlier literature and fixed the homo- 
logy of parts which had been variously interpreted by different 
workers. Two of his statements regarding the fasciculus communis 
are worthy of notice as supporting the description which I have 
given: 1) the fasciculus communis is always mesial to the other 
sensory systems (acusticum and spinal V) in the medulla and at its 
caudal end is connected with its fellow across the middle line; 
2) in most fishes examined its “caudal limit was apparent and 
MAYSER’s view that this as well as the spinal V was continuous 
with the gelatinosa of the myel, is questionable’. In some cases, 
Zool, Jahrb. XV, Abth. f. Morph, 12 
