186 J. B. JOHNSTON, 
b) Cerebellum. 
Fusari (87) describes in the molecular layer of the cerebellum 
of Teleosts PURKINJE cells irregularly arranged in the inner part 
of the layer and in the Grenzschicht, and smaller cells with den- 
drites unlike those of the PuRKINJE cells scattered throughout the 
layer. All the neurites are directed centrally; some make up the 
Grenzschicht, others pass through it and break up in the granular 
layer, while some form a central layer within the granular. Many 
neurites of the second kind of cells go toward the periphery and 
form a layer upon the surface but eventually join the central tracts. 
The Grenzschicht is formed wholly of fibres. The granular layer 
contains small rounded cells whose neurites are soon lost, cells 
whose neurites behave like those of the molecular layer, cells with 
short neurites, and cells whose neurites enter the central layer of 
fibres. The arrangement of cells and fibres in the valvula is as in 
the molecular layer. 
SCHAPER (93) describes in detail the PURKINJE cells of the 
Teleost cerebellum in both young and mature condition. The 
neurites run into the central fibre mass. Collaterals go to the 
molecular layer or among the PuRKINJE dendrites. The cells de- 
scribed by FuUSARI as PURKINJE cells were probably other cells 
which lie among the PURKINJE cells and send their neurites to 
break up in the granular layer. The granule cells correspond to 
the small granule cells of the Mammalian cerebellum. Their neurites 
always enter the molecular layer where they undergo T-division, one 
branch going to either side of the brain. The cells of the molecular 
layer are bipolar with dendrites of extraordinary length parallel with 
the surface. Their neurites run among the PURKINJE cells and are 
lost. They may end in baskets around the bodies of the PURKINJE 
cells, in which case these cells would correspond to the Mammalian 
Korbzellen. Small multipolar cells are also present whose neurites 
were not found. Two kinds of fibres enter the cerebellum and end 
in the molecular layer. One ends with a delicate end-brush, with 
varicosities and often with end-knobs. The other ends with an 
“äusserst zarten Geflecht” immediately outside of or between the 
PURKINJE cells. ScHAPER found no fibres ending in the granular 
layer or the fibre bundles. 
SCHAPERS account of the development of the cerebellum in 
Teleosts (94a and b) shows that the cerebellum is derived from a 
