440 P. W. WHITING 
curves would of course be in the opposite direction from that 
assumed for the inhibitor curves. 
While the curves for inhibitors have all been drawn for con- 
venience to the same form, it is obvious that the facts are in 
agreement with the supposition that the curves represent waves 
of slightly different lengths. In general the crests are at base 
and outer margin, while the troughs are in line with the median 
spots. Dark shortens the wave, making the trough slightly 
deeper. Sooty lengthens the wave considerably, making the 
trough shallower. Black merely reduces quantitatively without 
changing the form. 
Changes in length of waves may be compared to the effect 
of the different factors in the banding series in cats (Whiting, 
'18). Bands of three different widths as seen in tabby cats are 
determined by three factors apparently allelomorphic. The 
narrower bands are dominant over the wider. It seems probable 
that in this case the bands represent waves of varying metabolic 
activity rather than concentration of definite enzymes or 
inhibitors. 
Change in quantity of inhibitor without change of form of 
waves may be compared to agouti series in mammals. In- 
dividual hairs show bands of yellow more or less wide according 
to the quantity of inhibitor for black present. It is probable 
that the length of waves of concentration is not modified. 
