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Show 64 • ••• • • DARWINISM VARIATION OF 40 MALES OF AGELifUS A~CENIGEUS. Length of Bill. .:.:•: :.::.·.•· .: . • • Tot':,t LeJth of Bird. • •·••·•·• •t.•.•.•.•. •••••.•. • •• Length of Tail. • ••• . ••• ·.:.~.:::.::.:::.· ... LengJ of Wing. •• ••• •••••• •• •••••• ••••••••••••• •••• ••• • Amount of Variation. BILL. 1 LENGTH 7 6 9 TAIL. 1 WING. 1 4 8 FIO. 10. CHAP. • • of variation of each part would increase also, n.t first rathrr rapidly and then more slowly j while gaps and irregularities Curves of Variation Fro. 11. would be gradually filled up, and at length the distrJmt ion of the dots would indicate a tolembly regular curve of donhlc curvature like those shown in Fig. 11. The great divergence •• m VARIABILITY OF SPECIES IN A STATE OF NATURE 65 of the dotf'l, when oven a few specimens arc compared, shows that tho cnrve, with high nnm hers, would he a flat one like the lower curve in the illustrn.tion hero given. This being the cas it would follow thn.t a very large proportion of the total number f individuals constituting a species would diverge considembly from its average condition as regards each part or organ; and as we know from the previous diagrams of variation (Figs. 1 to 7) that each part varies to a considerable extent, independently, the materials constantly ready for natural selection GARDINAL/8 VIRGIN/ANUS. 58 specimens. Florida. ••• : ..... :•: .•...•.... .. :. Tai~ ~ • • •••••••••••. ••••••••••• 0 ••••• Length of Bird . ••• • • •• •••• •••••••••• • •• •••••••• • ••••••• Wing. •• • •••• • • ••• •• ••••••• ••• •••••••••••••••••••••••••••••• ••• • • • •• {From Allen's Bi 1ds of Florida. P.281) FIO. 12 0$ 0 to act upon are abundant in quantity and very varied in kind. Almost any combination of variations of di stinct parts will be available, where required; and this, as we shall see furth er on, obviates one of the most weighty objections which hn.ve been urged against the efficiency of natural selection in producing new species, genera, and higher groups. Vm·iat1on in the Mammalia. Owing to the gcneraJly hrgc size of this class of animals, and the comparatively small number of nn.turalists who study them, large se ries of specimens are only occasionally examined F |