No. 383.] BASIS FOR A THEORY OF COLOR VISION. 847 
would be determined by the number of fibrils in the lineal series 
and upon the difference in length between adjacent fibrils. 
The precise colors exhibited at any part of the cone would 
T T 
a tal 
KZ 4 
PAs 
ROS ais 
T 
PRT 
S , Pecten; nat, Acilius; 
D, Lycosa ; E, Tabanus; F, Bdellostoma; G, np eni H, Pen 
depend on the length of the fibrils at that point, while the 
range of colors exhibited would depend on the difference in 
length between the longest and the shortest fibrils. But the 
fibrils at different levels would not be equally luminous ; first, 
since the physical and chemical properties of protoplasm must 
set a limit to the length of ether waves to which such fibrils 
can respond, it is probable that the fibres of medium length 
would respond better to their appropriate stimuli than the 
extremely long or short ones. And again, as already pointed 
out, since the series of fibrils terminate abruptly at the base 
and at the apex of the cones, unsymmetrical luminosity curves 
for the red and violet light should be produced with maxima, 
respectively, at R and V, while the luminosity curve of the inter- 
mediate yellow-green fibrils should be symmetrical. But since 
there is a double summation of stimulation in the middle region 
of the cones, — due to the partial stimulation of the fibrils that 
are shorter and those that are longer than the mean, — the 
