Atavism in Guinea-Chicken Hybrids 745 
part, such as an abundance of black pigment, more or less of a 
reddish coloring matter, and the white pattern already described 
which in general alternates with the pigmented areas. White 
in feathers, as is well known, is not due to a pigment, but is the 
result of the diffractions and reflections of light from innumerable 
minute interstices. Since the pattern in question is prevalent 
in some of its modifications in both guineas and pheasants it has 
not been swamped when two such otherwise divergent forms as 
guinea and chicken have been merged, but the underlying struc- 
ture necessary for its appearance has persisted 1 in these particular 
cases and the pattern has come once more into evidence through 
the suppression of the moxe recent features which obscure it in the 
normal parent forms. ‘The very fact that this modified striping or 
barring is met with even yet in so many Phasianinz and Numi- 
dinz shows that it is a fundamental structure which has not been 
seriously disturbed by later acquisitions. 
