The brain of Acipenser. 169 
question is still an open one, however, the two latest papers on 
the Teleost brain having described VIII fibres going to the opposite 
side (cf. page 171 below). 
VAN GEHUCHTEN (94) describes a descending VIII tract im- 
pregnated with silver in the trout. This may be the spinal VIII, 
but as he does not describe the end-nucleus or denote its caudal 
extent, it is impossible to know. The fibres give off collaterals to 
the neighboring grey matter. He does not mention other bundles. 
GORONOWITSCH describes the acusticum under the name of the 
dorso-lateral tract. He describes the entrance of the lateral line X, 
its ascending and descending tracts, the descending being the larger. 
The ascending bundle probably enters the cerebellum. The lateral 
line VII (Zrig. IT) enters as two roots, one (7. II d) into the “Lobus 
trigemini”, the other (7. Iv) into the dorso-lateral tract. The “Lobus 
trigemini” consists of a peripheral fibre layer and an internal mass 
of small and large cells whose processes form the greater part of 
the fibre layer. From the fibre layer arises the root “7. II dors”. 
Arcuate fibres end in part among the PURKINJE cells and in part 
in the “Lobus trigemini” itself. The ventral root enters the acusticum 
and forms ascending and descending tracts, the ascending running 
to the cerebellum. The descending tract he supposed to be equi- 
valent to the spinal V of Teleosts. The VIII enters the ventral 
part of the dorso-lateral tract and forms an ascending tract to the 
cerebellum and a descending tract whose ending was not determined. 
In addition, the root receives some fibres from the fasciculus longi- 
tudinalis posterior and some from cells which he calls Acusticus- 
zellen. The fibres which GORONOWITSCH describes as arcuate fibres 
ending in the “Lobus trigemini”, arise in that lobe and run with 
those from the acusticum as internal arcuate fibres (page 82). The 
fibres which are said to enter the VIII from the fasciculus long. 
post. and from the Acusticuszellen do not exist. I have shown, 
however, that some VIII fibres break up in end-branches around 
certain cells lying near the cavity which I take to be the Acusticus- 
zellen. 
Kinesspury (97) traced the incoming bundles of the VIII both 
caudad and cephalad for a short distance. The relation of the 
acusticum to the cerebellum is important. The molecular layer of 
the cerebellum extends caudad over the oblongata, “and in Ganoids 
and Teleosts, so far as investigated, it is associated only with the 
acustic and lateral line system of nerves, the acusticum”. é; 
