The Duke of Falvertoon was one of those human hors d'oeuvres that stimulate the public appetite for sensation without giving it much to feed on. As a mere child he had been precociously brilliant; he had declined the editorship of the Anglian Review at an age when most boys are content to have declined mensa, a table, and though he could not claim to have originated the Futurist movement in literature, his "Letters to a possible Grandson," written at the age of fourteen, had attracted considerable notice. In later days his brilliancy had been less conspicuously displayed.
from The Unkindest Blow, a short story by Saki
What is the role of "those"?
What is the differende between "one of those human hors d'oeuvres" and "one of human hors d'oeuvres"?