Hmm. According to that 1879 novel, it's a guinea pig-- that is,
at least Molesworth's character calls the pet guinea pig a
cochon de Barbarie-- but according to Wikipedia (below), the French for
guinea pig is
cochon d'Inde (or
cobaye):
"Whatever the reason, this perception of pigginess occurred in many languages other than
English; the
German word for them is
Meerschweinchen,
literally "Little Sea Pigs" (sailing ships stopping to reprovision in
the New World would pick up stores of guinea pigs, which provided an
easily transportable source of fresh meat), the
Russian word for them is morskaja svinka (Sea Pig; Морская свинка), the
French word is
Cochon d'Inde, (Indian pig), the common Spanish word is 'conejillo de Indias' (Indian bunny rabbit), the
Dutch used to call it
guinees biggetje (Guinean piglet), in Sweden they are called
marsvin (a combination of the Latin word
mare for ocean, and Swedish
svin which means pig) and in
Greek they are called 'indika xoiridia' (Small Indian Pigs ; ινδικά χοιρίδια). The
scientific name of a common species is
Cavia porcellus, with
orcellus">porcellus being
Latin for 'little pig.' "
So the character must have been referring to another animal? Curiouser and curiouser.
PS: Cannot get into this site, but I found this intriguing excerpt:
With that he sang with quite a French entrain and English
accent the famous song of the day, called "Le Cochon de Barbarie."