Galdós's use of social types who were representative of Spanish society was not new, and nor was the placing of these characters within a Darwinian social scheme. However, one of the aims of this study is to show that while some of those who preceded Galdós in both these areas were a direct influence upon him, and while Galdós may have taken many pointers from these literary predecessors, the Darwinian scheme of social species was a genuine point of departure for Galdós's writing.

Born in 1843, Galdós may have been aware of transformational if not evolutionary theories from a reasonably tender age, but it is from the influx of books and articles which appeared in Spain in the 1860s, 1870s and 1880s that the influence of such ideas can be more accurately gauged. In what remains of Galdós's personal library there are several works concerned with evolutionary theories. Of particular interest among these is La creación by Edgar Quinet, which to judge from its present physical state has clearly been well read. Quinet is not only well-versed in current schools of evolutionary thought, but also has an understanding of the history of evolutionary theories, frequently acknowledging, for example, that economists and historians arrived at these ways of thinking before the naturalists.

Closer to home Galdós had a source of inspiration which he appears to have tapped quite freely, namely the costumbrista works of Ramón de Mesonero Romanos and Mariano José de Larra. With the former, Galdós was to develop a friendship based on a mutual respect borne out in their correspondence.

In seeking to determine the importance of the concepts of species and type in Galdós's work it is first necessary to discuss briefly what was understood by these terms in the nineteenth century. When Galdós started to pen articles in Madrid, the Origin had been published only six years before (1859) in Britain, and would not appear fully in Spanish translation for another twelve years. The Darwinian debate started later and more slowly in Spain than in many other parts of Europe, and it was not until after the Gloriosa that the trickle of articles on modern empirical science became a torrent. Therefore, the pre-existing concepts of species and types, and the impact that Darwinism had upon them, are the areas that demand examination.