Note 649 — Chapter XVII · ON THE THEORY OF TRANSFORMATIONS, OR THE COMPARISON OF RELATED FORMS*
Reading edition
Thus Ammonites erugatus, when compressed, has been described as A. planorbis: cf. Blake, J. F., Phil. Mag. (5), VI, p. 260, 1878. Wettstein has shewn that several species of the fish-genus Lepidopus have been based on specimens artificially deformed in various ways: Ueber die Fischfauna des Tertiären Glarnerschiefers, Abh. Schw. Palaeont. Gesellsch. XIII, 1886 (see especially pp. 23–38, pl. I). The whole subject, interesting as it is, has been little studied: both Blake and Wettstein deal with it mathematically.