What's the difference between harmonica and harmonicon?

Harmonica

Definition:

(n.) A musical instrument, consisting of a series of hemispherical glasses which, by touching the edges with the dampened finger, give forth the tones.
(n.) A toy instrument of strips of glass or metal hung on two tapes, and struck with hammers.

Example Sentences:

(1) Sting is sitting on a bar stool in a white T-shirt and grey camouflage-patterned combat trousers, playing a harmonica.
(2) There are banjos and harmonicas, songs harking back to the old-time tunes she grew up listening to in Golden, Texas (population: 600).
(3) With those shades and that blank expression he communicated something far more menacing to middle-class America than the curly haired man with the harmonica.
(4) After passing on that, and the Bob Dylan 1999 tour harmonica ($2,000), I stop at the shrine to Elliott Smith.
(5) You can sort of tell from Who Are You – which from its harmonica intro and ponderous gait sounds like Dylan blowing his harp through the Smiths' How Soon Is Now – that Cox doesn't move like Jagger, but more like Morrissey.
(6) In March, 2004, these included a harmonica, two bracelets, a ring, a framed picture of a girl dancing on the brow of a hill and the reminder from a packet of Swan rolling papers that prompted Drake to call his first album Five Leaves Left.
(7) You keep expecting the song, usually just played with piano and the occasional harmonica, to reach a dramatic climax, but instead it fades away.
(8) Middleton will host a final local health summit on his last working day this Friday, at the vast Balaji Hindu temple in Tividale , before heading off for retirement, when he hopes to have more time for his other great passion, the blues harmonica.
(9) "When I heard Goodnight Irene by Leadbelly, with Sonny Terry on harmonica, that was it.
(10) Papers have been withheld from Chaplin's MI5 file to protect the names of informants though there are unexplained, probably inconsequential, references to Jimmy Reid, the communist Scottish trade unionist; Larry Adler, the harmonica virtuoso who left his native US where he was branded a communist and blacklisted; and Humphrey Lyttelton, the Eton-educated jazz musician who once described himself a "romantic socialist".