1428 
Finally it must be mentioned that the tractus spino-cerebel- 
laris ventr. and dors. in Scyllium may be easily traced as a 
compact bundle, and that I could find no fibres going from it to 
the nuclei lateralis; they all end in the corpus cerebelli. HeRRIOK 
also says of the Amphibians that there is no connection between 
the tr. spino-cerebellaris (which ends in the cerebellum itself) 
and the area acustico-lateralis; so in this respect too, the relations 
as found in sharks show a homology to those of the amphi- 
bians, since the spino-cerebellary tracts in the Selachians also 
end in the corpus cerebelli. 
Amphibians. 
Herrick ') has made an exhaustive investigation of the cerebellum 
in urodele amphibians, and I cannot refrain from mentioning such 
of his results as are the most important for my research. 
The cerebellum of tailed amphibians is formed by the tissue of 
the walls of the recessus lateralis of the 4" ventricle, while the 
roof of the 4% ventricle is almost entirely ependymal and contains 
but little nervous tissue. 
Further forward, frontally, the recessus forms a tiny pocket, the 
diverticulum anterius. Nervous cerebellar tissue is found on every 
side of the diverticulum anterius, and cerebellar tissue is also found 
in the antero-medial wall of the recessus lateralis and on its floor. 
The main mass of the cerebellum of the higher amphibians and 
the reptiles appears to arise in the mesio-frontal part of the wall 
of the recessus lateralis in the urodele Amphibians. For this reason 
Herrick names this part of the recessus, even though it is very 
poorly developed, the corpus cerebelli. The corpora cerebelli on 
both sides are joined by a dorsal commissure. This commissure in 
the Amphibians forms, where the roof of the diverticulum anterius 
is ependymal (instead of nervous as is the case in Necturus), the 
only nervous portion of the roof of the 4" ventricle. 
The floor of the recessus lateralis shows a curve which Herrick 
has called eminentia ventralis cerebelli. It lies on the level near the 
trigeminus entrance. The postero-lateral wall of the recessus is also 
thickened, that is the lobus anterior of the area acustico-lateralis. 
The tissue of the eminentia ventralis cerebelli now passes over 
into the corpus cerebelli. 
The uppermost edge of the lateral wall of the recessus contains 
!) Herrick: loe. cit. 
