1030 The American Naturalist. [November, 
mous nature is so changed as to induce it to polygamy. We 
may infer, therefore, that sexual power and high sexual characters 
go hand in hand, and that in proportion to the advance toward 
organic perfection, virility increases. A canary, so domesticated, 
probably would not at first endeavor to mate with more than 
one female, if not induced to do so by the breeder; but in a 
cage where one male is associated with many females his flirta- 
tions are notorious, and like human polygamists he practices 
favoritism,—one is his mistress, the rest, according to his incon- 
stancy, maids of dishonor. No less convincing is the case of 
the wild mallard (Anas boschas). If amale and several females be 
captured and restricted to the limits of a small pond, and receive 
proper care, the latter will all receive the voluntary attentions 
of the drake, though in a state of nature he contents himself 
with one. 
Especially, if not exclusively, does this hold true with monog- 
amists presenting strong sexual differences. On the contrary, 
we should observe that species of slight sexual dissimilarity (and 
therefore plainly colored), however subjected to long domestica- 
tion, retain with tenacity their original monogamous habits. For 
example, the male guinea fowl (Numida meleagris), when forced to 
associate with more than a single female, chooses one and ignores 
the rest; and’ Dixon asserts, in his book of “ Ornamental Poul- 
try,” that the eggs of one female alone will, in such a case, prove 
fertile. Domestication, therefore, in the abstract will avail noth- 
ing unless seconded by previous condition of high ornamentation - 
and strong sexual differences, or unless directed to the production 
of these. In the breeding of guinea fowl high coloration was not 
an object; in the canary it was a most desirable production; in 
the mallard it already existed, and required but slight change of 
environment and food habits to induce its possessor to alter its 
Marriage code. 
Putting facts together, I am induced to believe: xst, That 
sexual selection in favor of beauty of color and form of sec- 
ondary characters, whether voluntary or the result of man’s inter- 
ference, is always accompanied by proportionate increase of sexual 
vigor. 2d, That such increase is a provision of nature to 
: * 
