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Show 3DG GENERAL SUMMARY PAnT Ln .. through the laws of variation and natural selection than to explain the birth of the individnal through th~ laws of ordinary reproduction. The birth both of the species and of the individual are equally parts of that grand sequence of events, which our minds refuse to accept as the result of blind chance. ~rho understanding revolts at such a conclusion, whether or not we are able to believe that every shght variation of structnre,- the union of each pair in marriaO'e,-the disse- • • • t:> mmatwn ot each sccd,-ancl other such events, have all been ordained for some special purpose. Sexual selection has been treated at great length in these volume. ; for, as I have attempted to shew, it has played an important part in the history of the organic ~orld. As summaries have been given to each chapter, 1t would be superfluous here to add a detailed summary. I am aware tlmt much remains doubtful, but I have endeavoured to give a fair view of the whole case. In the lower divisions of the animal kin()'dom sexual l . 0 ' se ectwn seems to have done nothing: such animals are often affixed for lifo to the same spot, or have the two sexes combined in the same individual or what is still more important, their perceptive and intellectual faculti<-JS are not sufficiently advanced to allow of the feelings of love and jealousy, or of the exe1·tion of choiee. When, however, we come to the Arthropoda and Vertebi~ ata, even to the lowest classes in these two great SubKmgcloms, sexual selection bas effected much· and it deserves notice that we here find the intellectu~l faculti~ s developed, but in two very distinct lines, to the highest standard, namely in the Hymen0ptera (ants, bees, &c.) amongst the Arthropoda, and in the Mammalia, including man, amongst the Vertebrata. In the most distinct classes of the animal kingdom, CnAI'. XXI. AND CONCLUDING REMARKS. 397 with mammals, birds, reptiles, fishes, insects, and even crustaceans, tho differences between the sexes follow almost exactly tho same rules. The males are almost always the ·wooers; and they alone arc armed with special weapons for fighting with their rivals. They are generally stronger and larger than the females, and are endowed with the requisite qualities of courage and pugnacity. They arc provided, either exclusively or in a much biaher dcaree than the females, with organs for producin~ vocal ~r instrumental music, and with odoriferous glands. 'l'hey are ornamented with infinitely diversified appendages, and with the most brilliant or ·conspicuous colours, often arranged in elegant patterns, whilst the females arc left unadorned. ·when the sexes differ in more important structures, it is the male which is provided with 8pecial sense-organs for discovering the female, with locomotive organs for reaching her, and often with prehensile organs for holding her. rrhese various structures for seeming or charming the female arc often developed in the male during only part of the year, namely the breeding season. They have in many cases been transferred in a greater or less degree to the females; and in the latter case they appear in ihcr as mere rudiments. They are lost by tho males after emasculation. Generally they are not developed in the male durjng early youth, but appear a short time before the age for reproduction. Hence in most .cases the young of both sexes resemble each other; and the female resembles her young offspring throughout life. In almost every great class a few anomalous cases occur in which there has been an almost complete transposition of the chamcters proper to the two sexes ; the females assuming characters which properly belong to the males. This surprising uniformity in the laws regulating the differences between the sexes in so many |