The Descent of Man

whilst young; and I infer that this is a case of
premature breeding, because they have not as
yet acquired their fully-developed claspers. All
such facts are highly interesting, as bearing on
one means by which species may undergo great
modifications of character.) If, on the other
hand, the young never succeeded in obtaining a
female, the habit of early reproduction would
perhaps be sooner or later eliminated, from
being superfluous and entailing waste of power.
The plumage of certain birds goes on increasing
in beauty during many years after they are fully
mature; this is the case with the train of the
peacock, with some of the birds of paradise,
and with the crest and plumes of certain
herons, for instance, the Ardea ludovicana. (40.
Jerdon, 'Birds of India,' vol. iii. p. 507, on the
peacock. Dr. Marshall thinks that the older and
more brilliant males of birds of paradise, have
an advantage over the younger males; see 'Ar-