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Show 162 SEXUAL SELECTION: BIRDS. PART II. siderable length, even at greater length than its i~tri~sic importance deserves; for various curious collatera pomts may thus be conveniently considered. Before we enter on the subject of colour, more especially in reference to Mr. W allac~'s. conclt~sions, it may be useful to discuss under a similar pomt of view some other differences between the sexes. A breed of fowls formerly existed in Germany 5 in which the hens were furnished with spurs; they were good layers, but they so greatly disturbed their ~ests wit~1 their spurs that they could not be allowed to sit on the1r own eggs. Hence at one time it appea~·ed to n~e probable that with the females of the wild Gallmacero the development of spurs had been checked throug~ natural selection, from the injury thus caused to their nests. This seemed all the more probable as the wingspurs, which could not be injurious during nidification, are often as well developed in the female as in the male ; though in not a few cases they are rather larger in the male. When the male is furnished with legspurs the female almost always exhibits rudiments of them,-the rudiment sometimes consisting of a mere scale, as with the species of Gallus. Hence it might be argued that the females bad aboriginally been furnished with well-developed spurs, but that these bad subsequently been lost either through disuse or natural selection. But if this view be admitted, it would have to be extended to innumerable other cases; and it implies that the female progenitors of the existing spurbearing species were once encumbered with an injurious appendage. In some few genera and species, as in Galloperdix, Acomus, and the Javan peacock (Pavo muticus), the 6 Bechstein, 'Naturgesch. Deutschbnds,' 1793, B. iii. s. 339. (;liAr. XV. DEVELOPMENT OF SPURS. 1G3 females, as well as the males, possess well-developed spurs. A1:e we to infer from this fact that they construct .a different sort of nest, not liable to be injured by thmr spurs, from that made by their nearest allies, so that there has been no need for the removal of their spurs? ?rare we to suppose that these females especially reqmre spurs for then· defence? It is a more probable conclusion that both the presence and absence of spurs in the females result from different laws of inherita? ce hav~ng prevaile~ independently of natural selectiOn. ~1th the many females in which spurs appear as rudiments, we may conclude that some few of the succes~ive va!l.'iations, through which they were deve~ oped m the males, occurred very early in life, and were .as a consequence transferred to the females. In tho other and much rarer cases, in which the females possess fully developed spurs, we may conclude that all the successive variations were transferred to them ; and t~at they gradually acquired the inherited habit of no.t disturbing their nests. The vocal organs and the variously-modified feathers for pr?ducing sound, as well as the proper instincts for u~mg them, often differ in the two sexes, but are sometimes the same in both. Can such differences be acco~nt~d for by the males having acquired these organs ~nd I~~tmcts, whilst the females have been saved from mher1tmg them, on account of the danger to which they would have been exposed by attractino- the attention of birds or beasts of prey ? This 0 does not 'See~ to me probable, when we think of the multitud-e <Of ?nds.which ~ith impunity gladden the country with therr vmces durmg the spring.6 It is a safer conclu- J. : Daines Banington, however, thought it probable(' Phil. Transact.' 7t3, p. 164) thnt few female bil'ds sing, because the talent wou!J have l\1 2 |