accomplishments would probably have most chance of success when the females arrived. Darwin himself said that nothing is commoner than for animals to take pleasure in practising whatever instinct they follow at other times for some real good. These manifestations are primarily for the sake of producing sexual tumescence, and could not well have been developed to the height they have reached unless they were connected closely with propagation. That they may incidentally serve to express "gladness" one need not feel called upon to question. Another observer of birds, Mr. E. Selous, has made observations which are of interest in this connection. He finds that all bird-dances are not nuptial, but that some birds--the stone-curlew (or great plover), for example--have different kinds of dances. Among these birds he has made the observation, very significant from our present point of view, that the nuptial dances, taken part in by both of the pair, are immediately followed by intercourse. In spring "all such runnings and chasings are, at this time, but a part of the business of pairing, and one divines at once that such attitudes are of a sexual character.... Here we have a bird with distinct nuptial (sexual) and social (non-sexual) forms of display or antics, and the former as well as the latter are equally indulged in by both sexes." (E. Selous, _Bird Watching_, pp. 15-20.) The same author (ibid., pp. 79, 94) argues that in the fights of two males for one female--with violent emotion on one side and interested curiosity on the other--the attitude of the former "might gradually come to be a display made entirely for the female, and of the latter a greater or less degree of pleasurable excitement raised by it, with a choice in accordance." On this view the interest of the female would first have been directed, not to the plumage, but to the frenzied actions and antics of the male. From these antics in undecorated birds would gradually develop the interest in waving plumes and fluttering wings. Such a dance might come to be of a quite formal and non-courting nature.