Wolviex
I wonder if you mean the swords with the so called "boat-shell" hilt ("
guarnición de barquilla", in Spanish), they are not exactly what one would call smallswords, they are more of a rapier, morphologically speaking, though as they are typical of the 18th century such definition would be somewhat chronologically problematic.
An example of what I'm talking about
:
(Images courtesy of Sala Antiguedades)
They normally feature a quote strong blade, and are associated with a military context.
Spain kept rapiers in use when the rest of Europe had already adopted some time ago the smallsword fashion. For civilian use, since the last years of the 17th century, the rapier was slowly being substituted by the smallsword, but the definitive push was given by the introduction of the Bourbon Dynasty on the Spanish Throne in 1700. Even so, one may find some oddities from that time, like rapier blades with smallsword hilts... and these "boat-shell" hilt swords that seem to had been use for the most part of the 18th century.
This type of hilt, must be said, was used in smallswords, also, with some variations that tended to more delicate lines.
See for example:
(Image courtesy of Armas Don Diego)
I wonder if I'm stretching the "Ethnographic" term, here...