Atavism in Guinea-Chicken H ybrids rw 
probably derived from the former, such as is found at the base of 
the feathers of the regressive forms and on certain of the wing 
feathers and at the base of many other feathers of the ordinary 
domestic guinea. 
There is evidence, furthermore, in the plumage of Numida 
meleagris that in the formation of the heavier barred type only 
every other one of the bars of the primitive pattern have been 
thickened (cf. Figs. 16, 17, 19, 20, 25, Plate IV), the alternate 
bar tending to disappear. 
The sequence of the pattern in the guineas would seem to be 
from what originally was probably a simple irregular specking 
with white, to the narrow fine vermiculations such as now exist 
most characteristically in Agelastes meleagrides followed by a 
broader barring of white as evidenced in certain feathers of the 
domestic guinea. This barring has been largely transformed or 
is in process of transformation into a conspicuous white dotting 
as seen in Numida meleagris and Acryllium vulturina. Certain 
feathers of Acryllium are even a step further in advance since the 
dots have seemingly merged to form a longitudinal stripe. 
Thus, it is an interesting fact to note that in both the sub-families 
Phasianinz and Numidinz, in various comprehensive groups of 
genera and species, there are certain basic tendencies for particu- 
lar elements of the coloration, such as the formation of eye-spots, 
barring, and the like, to follow along definite paths of develop- 
ment. When arranged with reference to one of these elements, 
such for example, as barring, which is one of the most universal, 
instead of possessing distinct and unrelated markings, the differ- 
ent species in a given group are seen to be standing merely at dif- 
ferent levels in the development of one, or at most a few, contin- 
uous progressions in the development of the special pattern in 
question. Since when so grouped the gradation in pattern is as 
much in evidence between collateral kinsmen as between those of 
direct lineage, one can only conclude that the bias toward a par- 
ticular line of patterns is the product of fundamental protoplasmic 
peculiarities implanted in the group as a whole. In a few in- 
stances the characteristic design may be wholly obscured; in many 
cases it has been warped and twisted, as it were, possibly by nat- 
