742 Michael F. Guyer 
least, this would seem to be the most reasonable interpretation 
that presents itself. It might be urged, of course, that as regards 
the white banding, for instance, it is simply a case of “new varia- 
tions which happen to hit the old mark.” But why in the very 
limited number" of known guinea-chicken hybrids has it “hap- 
pened ” in five instances, in America recently, and earlier in a similar 
hybrid in England which dates from 1845? And why as regards 
various other features of pronounced hybrids have so many “old 
marks” been hit? Why, indeed, as pointed out by Darwin” 
on the authority of Tegetmeier, is there a very general tendency 
among gallinaceous birds for a barred pattern to appear when 
pure-bred forms are crossed? If we argue that the very nature 
of the protoplasm of the two species hybridized limits the number 
of possible variations and hence makes it probable that a given 
variation may be hit upon repeatedly, in admitting this markedly 
restrictive and hence determining character of the protoplasm 
do we not admit that the phenomenon is hereditary (that is, rever- 
sionary) in nature rather than fortuitous ? 
The great question, of course, which presses for solution is how 
such returns come to pass, and it must be admitted that concern- 
ing the real nature of the processes we are almost as much inthe 
11 Still farther confirmatory evidence in this particular has come to my knowledge since my manuscript 
was sent to press. I have had the opportunity of examining seven other guinea-chicken hybrids; two in 
the South Kensington Museum of London, and five in the American Museum of Natural History in 
New York City. Of the former, one had been received from Brazil in 1899 and the other from Kalka, 
India, in 1902. The superficial feathers of the Brazilian form were white, splashed somewhat with red, 
but when these were pushed to one side various underlying feathers showing pronouncedly the charac- 
teristic chevronlike markings were disclosed. The Indian form, of which the plumage was heavily 
washed with reddish brown, likewise exhibited the chevron barring, especially on the underlying feather. 
The five specimens in the American Museum of Natural History were the donation of Dr. Juan Vilaro 
of Cuba, according to whom such hybrids are by no means rare in Cuba. (Hybrids between the Game 
Cock and the Guinea Fowl, by Juan Vilaro, M.D., Bul. Am. Mus. of Nat. Hist., vol. ix, article xviii, 
August 21, 1897.) Four of these birds, although all of separate parentage, show at first glance an abund- 
ance of the markings in question. The fifth bird is white, the offspring of a pure white guinea-fowl and 
awhite hen. Notwithstanding the lack of pigment, many of the feathers of this white hybrid, upon close 
scrutiny, show the presence of the chevron-like bands across the vane, thus demonstrating that the char- 
acteristic barring is due primarily to structural features of the vane itself, the pigment being a secondary 
factor which by its presence serves to emphasize to the eye certain regions of the fundamental structural 
pattern. 
* Darwin, Ch.: The Variation of Animals and Plants under Domestication. Vol. i, p. 295;vol. ii, 
p- 17- 
