1425 
The nucleus lateralis is connected with fibres from the cortex 
cerebelli and fibres which must be regarded as arcuate-fibres go out 
from it ventrally to the mid-brain and bulb. This proves their 
similarity with cerebellar nuclei of higher vertebrates. They are 
however still in connection with the vestibularis and lateralis system. 
Fibres which come from the lobus lateralis (the area-vestibulo- 
lateralis of most writers) and go dorsally in the direction of the 
cerebellum, give off fibres which split off in the nucleus lateralis 
cerebelli. These may be end-ramifications of neurites as well as col- 
laterals of fibres which send their terminals higher up. 
Especially in Selache maxima it was clearly visible that from a 
bundle of Nv. vestibularis, fibres curved off to the Ne. lateralis 
cerebelli, as is also described by Voormorve '). Of the Fibrae arcuatae, 
which proceed from the nucleus lateralis cerebelli, some pass frontally 
to the midbrain and decussate the raphe there. Their endpoint is 
difficult to determine, as they are lost to sight in the Weicert 
preparations in the basis of the aqueduct, some in the formatio 
reticularis, some in the environs of the IIL. nuclei. 
A red nueleus is hardly visible in sharks’), so that this cannot 
be considered as the main ending to establish the homology between 
these fibrae arcuatae of the Selachians and the brachium conjunc- 
tivium of the mammals. 
Nevertheless the idea of this homology forces itself upon us, the 
more so as’ in the higher animals the red nucleus is not the only 
end-point of the tr. cerebello-mesene. crue. 
It is important to be able to ascertain that the two systems 
rebellen ze CAA nebe le 
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Var Cah and 
Fig. 2. Seyllium caniculum. 
1) VoorHoeve. Not yet published. 
2) S. pe Lanar. The red nucleus in Reptiles. Proceedings of the Kon. Akad. 
v. Wetensch. Amsterdam April 1912, 
