Mill, J. S. (1875). Of classification by series. In J. S. Mill, System of logic, ratiocinative and inductive, being a connected view of the principles of evidence and the methods of scientific investigation (pp. 288-295). London, Great Britain: Longmans, Green, Reader, and Dyer.
http://dx.doi.org/10.1037/12863-019
Topics covered in this chapter include: Natural groups should be arranged in a natural series; The arrangement should follow the degrees of the main phenomenon; -- which implies the assumption of a type-species; How the divisions of the series should be determined; and Zoology affords the most complete type of scientific classification. (PsycINFO Database Record (c) 2016 APA, all rights reserved)