Figure 2. Affinities and analogies among birds. From Swainson, W. 1836-1837. On the natural history and classification of birds. 2 vols. London: Longman, Rees, Orme, Brown, Green, and LongmanAffinities and analogies among birds. From Swainson, W. 1836-1837. On the natural history and classification of birds. 2 vols. London: Longman, Rees, Orme, Brown, Green, and Longman.